diff --git a/assets/test_prelude.ld b/assets/test_prelude.ld
index dfcb9f3..7021bf1 100644
--- a/assets/test_prelude.ld
+++ b/assets/test_prelude.ld
@@ -1211,7 +1211,35 @@ fn penwidth {
 
 box state = nil
 
+fn self {
+	"Returns the current process's pid, as a keyword."
+	() -> base :process (:self)
+}
+
+fn send {
+	"Sends a message to the specified process."
+	(pid as :keyword, msg) -> base :process (:send, pid, msg)
+}
+
+fn spawn! {
+	"Spawns a new process running the function passed in."
+	(f as :fn) -> base :process (:spawn, f)
+}
+
+fn yield! {
+	"Forces a process to yield."
+	() -> base :process (:yield)
+}
+
+fn msgs () -> base :process (:msgs)
+
 #{
+	self
+	send
+	msgs
+	spawn!
+	yield!
+
 	abs
 	abs
 	add
diff --git a/sandbox.ld b/sandbox.ld
index 07a0e48..6c454cc 100644
--- a/sandbox.ld
+++ b/sandbox.ld
@@ -1 +1,11 @@
-let true = false
+let pid = spawn! (fn () -> {
+  print! (self ())
+  print! (msgs ())
+})
+
+send (pid, :foo)
+send (pid, :bar)
+
+yield! ()
+
+:done
diff --git a/src/base.rs b/src/base.rs
index 7efa43f..d3ed96e 100644
--- a/src/base.rs
+++ b/src/base.rs
@@ -609,6 +609,7 @@ pub fn make_base() -> Value {
         ("number", Value::BaseFn(BaseFn::Unary("number", number))),
         ("pi", Value::Number(std::f64::consts::PI)),
         ("print!", Value::BaseFn(BaseFn::Unary("print!", print))),
+        ("process", Value::Process),
         ("random", Value::BaseFn(BaseFn::Nullary("random", random))),
         ("range", Value::BaseFn(BaseFn::Binary("range", range))),
         ("rest", Value::BaseFn(BaseFn::Unary("rest", rest))),
diff --git a/src/chunk.rs b/src/chunk.rs
index 6551278..7dfba57 100644
--- a/src/chunk.rs
+++ b/src/chunk.rs
@@ -20,6 +20,12 @@ pub struct Chunk {
     pub msgs: Vec<String>,
 }
 
+impl std::fmt::Display for Chunk {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(f, "Chunk.")
+    }
+}
+
 impl Chunk {
     pub fn dissasemble_instr(&self, i: &mut usize) {
         let op = Op::from_u8(self.bytecode[*i]).unwrap();
diff --git a/src/lib.rs b/src/lib.rs
index bbe9c50..063bee8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,7 +3,7 @@ use imbl::HashMap;
 use wasm_bindgen::prelude::*;
 
 const DEBUG_SCRIPT_COMPILE: bool = false;
-const DEBUG_SCRIPT_RUN: bool = false;
+const DEBUG_SCRIPT_RUN: bool = true;
 const DEBUG_PRELUDE_COMPILE: bool = false;
 const DEBUG_PRELUDE_RUN: bool = false;
 
@@ -84,8 +84,9 @@ fn prelude() -> HashMap<&'static str, Value> {
     compiler.compile();
 
     let chunk = compiler.chunk;
-    let mut vm = Creature::new(chunk, DEBUG_PRELUDE_RUN);
-    let prelude = vm.run().clone().unwrap();
+    let mut world = World::new(chunk, DEBUG_PRELUDE_RUN);
+    world.run();
+    let prelude = world.result.unwrap().unwrap();
     match prelude {
         Value::Dict(hashmap) => *hashmap,
         _ => unreachable!(),
@@ -146,10 +147,8 @@ pub fn ludus(src: String) -> String {
 
     let vm_chunk = compiler.chunk;
 
-    let vm = Creature::new(vm_chunk, DEBUG_SCRIPT_RUN);
-    let grip = World::new(vm);
-    grip.borrow_mut().run();
-    let world = grip.borrow();
+    let mut world = World::new(vm_chunk, DEBUG_SCRIPT_RUN);
+    world.run();
     let result = world.result.clone().unwrap();
 
     let console = postlude.get("console").unwrap();
diff --git a/src/vm.rs b/src/vm.rs
index bd1150d..add7909 100644
--- a/src/vm.rs
+++ b/src/vm.rs
@@ -4,7 +4,7 @@ use crate::op::Op;
 use crate::parser::Ast;
 use crate::spans::Spanned;
 use crate::value::{LFn, Value};
-use crate::world::Grasp;
+use crate::world::Zoo;
 use imbl::{HashMap, Vector};
 use num_traits::FromPrimitive;
 use std::cell::RefCell;
@@ -77,26 +77,35 @@ fn combine_bytes(high: u8, low: u8) -> usize {
     out as usize
 }
 
+const REGISTER_SIZE: usize = 8;
+
 #[derive(Debug, Clone, PartialEq)]
 pub struct Creature {
     pub stack: Vec<Value>,
     pub call_stack: Vec<CallFrame>,
     pub frame: CallFrame,
     pub ip: usize,
-    pub return_register: [Value; 8],
+    pub register: [Value; REGISTER_SIZE],
     pub matches: bool,
     pub match_depth: u8,
     pub result: Option<Result<Value, Panic>>,
     debug: bool,
     last_code: usize,
     pub id: &'static str,
-    pub world: Grasp,
     pub mbx: VecDeque<Value>,
     pub reductions: usize,
+    pub zoo: Rc<RefCell<Zoo>>,
+    pub r#yield: bool,
+}
+
+impl std::fmt::Display for Creature {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(f, "Creature. {} @{}", self.id, self.ip)
+    }
 }
 
 impl Creature {
-    pub fn new(chunk: Chunk, debug: bool) -> Creature {
+    pub fn new(chunk: Chunk, zoo: Rc<RefCell<Zoo>>, debug: bool) -> Creature {
         let lfn = LFn::Defined {
             name: "user script",
             doc: None,
@@ -106,8 +115,12 @@ impl Creature {
             closed: RefCell::new(vec![]),
         };
         let base_fn = Value::Fn(Rc::new(lfn));
+        Creature::spawn(base_fn, zoo, debug)
+    }
+
+    pub fn spawn(function: Value, zoo: Rc<RefCell<Zoo>>, debug: bool) -> Creature {
         let base_frame = CallFrame {
-            function: base_fn.clone(),
+            function,
             stack_base: 0,
             ip: 0,
             arity: 0,
@@ -117,16 +130,17 @@ impl Creature {
             call_stack: Vec::with_capacity(64),
             frame: base_frame,
             ip: 0,
-            return_register: [const { Value::Nothing }; 8],
+            register: [const { Value::Nothing }; REGISTER_SIZE],
             matches: false,
             match_depth: 0,
             result: None,
             debug,
             last_code: 0,
             id: "",
-            world: None,
+            zoo,
             mbx: VecDeque::new(),
             reductions: 0,
+            r#yield: false,
         }
     }
 
@@ -134,6 +148,11 @@ impl Creature {
         self.reductions += 1;
     }
 
+    pub fn reset_reductions(&mut self) {
+        self.reductions = 0;
+        self.r#yield = false;
+    }
+
     pub fn receive(&mut self, value: Value) {
         self.mbx.push_back(value);
     }
@@ -165,12 +184,21 @@ impl Creature {
         }
         let inner = inner.join("|");
         let register = self
-            .return_register
+            .register
             .iter()
             .map(|val| val.to_string())
             .collect::<Vec<_>>()
             .join(",");
-        println!("{:04}: [{inner}] ({register})", self.last_code);
+        let mbx = self
+            .mbx
+            .iter()
+            .map(|val| val.show())
+            .collect::<Vec<_>>()
+            .join("/");
+        println!(
+            "{:04}: [{inner}] ({register}) {} {{{mbx}}}",
+            self.last_code, self.id
+        );
     }
 
     fn print_debug(&self) {
@@ -179,12 +207,12 @@ impl Creature {
         self.chunk().dissasemble_instr(&mut ip);
     }
 
-    pub fn run(&mut self) -> &Result<Value, Panic> {
-        while self.result.is_none() {
-            self.interpret();
-        }
-        self.result.as_ref().unwrap()
-    }
+    // pub fn run(&mut self) -> &Result<Value, Panic> {
+    //     while self.result.is_none() {
+    //         self.interpret();
+    //     }
+    //     self.result.as_ref().unwrap()
+    // }
 
     pub fn call_stack(&mut self) -> String {
         let mut stack = format!("   calling {}", self.frame.function.show());
@@ -237,13 +265,54 @@ impl Creature {
         self.ip >= self.chunk().bytecode.len()
     }
 
+    fn handle_msg(&mut self, args: Vec<Value>) {
+        println!("message received! {}", args[0]);
+        let Value::Keyword(msg) = args.first().unwrap() else {
+            return self.panic("malformed message to Process");
+        };
+        match *msg {
+            "self" => self.push(Value::Keyword(self.id)),
+            "msgs" => {
+                let msgs = self.mbx.iter().cloned().collect::<Vec<_>>();
+                let msgs = Vector::from(msgs);
+                self.push(Value::List(Box::new(msgs)));
+            }
+            "send" => {
+                let Value::Keyword(pid) = args[1] else {
+                    return self.panic("malformed pid");
+                };
+                if self.id == pid {
+                    self.mbx.push_back(args[2].clone());
+                } else {
+                    self.zoo
+                        .as_ref()
+                        .borrow_mut()
+                        .send_msg(pid, args[2].clone());
+                }
+                self.push(Value::Nil);
+            }
+            "spawn" => {
+                println!("spawning new process!");
+                let f = args[1].clone();
+                let proc = Creature::spawn(f, self.zoo.clone(), self.debug);
+                let id = self.zoo.as_ref().borrow_mut().put(proc);
+                self.push(Value::Keyword(id));
+            }
+            "yield" => {
+                self.r#yield = true;
+                self.push(Value::Nil);
+            }
+            msg => panic!("Process does not understand message: {msg}"),
+        }
+    }
+
     pub fn interpret(&mut self) {
         loop {
             if self.at_end() {
                 self.result = Some(Ok(self.stack.pop().unwrap()));
                 return;
             }
-            if self.reductions >= MAX_REDUCTIONS {
+            if self.reductions >= MAX_REDUCTIONS || self.r#yield {
                 return;
             }
             let code = self.read();
@@ -321,27 +390,27 @@ impl Creature {
                     self.push(value.clone());
                 }
                 Store => {
-                    self.return_register[0] = self.pop();
+                    self.register[0] = self.pop();
                 }
                 StoreN => {
                     let n = self.read() as usize;
                     for i in (0..n).rev() {
-                        self.return_register[i] = self.pop();
+                        self.register[i] = self.pop();
                     }
                 }
                 Stash => {
-                    self.return_register[0] = self.peek().clone();
+                    self.register[0] = self.peek().clone();
                 }
                 Load => {
                     let mut value = Value::Nothing;
-                    swap(&mut self.return_register[0], &mut value);
+                    swap(&mut self.register[0], &mut value);
                     self.push(value);
                 }
                 LoadN => {
                     let n = self.read() as usize;
                     for i in 0..n {
                         let mut value = Value::Nothing;
-                        swap(&mut self.return_register[i], &mut value);
+                        swap(&mut self.register[i], &mut value);
                         self.push(value);
                     }
                 }
@@ -814,6 +883,7 @@ impl Creature {
                     self.push(Value::Partial(Rc::new(partial)));
                 }
                 TailCall => {
+                    self.reduce();
                     let arity = self.read();
 
                     let called = self.pop();
@@ -826,6 +896,10 @@ impl Creature {
                     }
 
                     match called {
+                        Value::Process => {
+                            let args = self.stack.split_off(self.stack.len() - arity as usize);
+                            self.handle_msg(args);
+                        }
                         Value::Fn(_) => {
                             if !called.as_fn().accepts(arity) {
                                 return self.panic_with(format!(
@@ -835,7 +909,7 @@ impl Creature {
                             }
                             // first put the arguments in the register
                             for i in 0..arity as usize {
-                                self.return_register[arity as usize - i - 1] = self.pop();
+                                self.register[arity as usize - i - 1] = self.pop();
                             }
                             // self.print_stack();
 
@@ -843,9 +917,9 @@ impl Creature {
                             self.stack.truncate(self.frame.stack_base);
                             // then push the arguments back on the stack
                             let mut i = 0;
-                            while i < 8 && self.return_register[i] != Value::Nothing {
+                            while i < 8 && self.register[i] != Value::Nothing {
                                 let mut value = Value::Nothing;
-                                swap(&mut self.return_register[i], &mut value);
+                                swap(&mut self.register[i], &mut value);
                                 self.push(value);
                                 i += 1;
                             }
@@ -936,6 +1010,7 @@ impl Creature {
                     }
                 }
                 Call => {
+                    self.reduce();
                     let arity = self.read();
 
                     let called = self.pop();
@@ -945,6 +1020,10 @@ impl Creature {
                     }
 
                     match called {
+                        Value::Process => {
+                            let args = self.stack.split_off(self.stack.len() - arity as usize);
+                            self.handle_msg(args);
+                        }
                         Value::Fn(_) => {
                             if !called.as_fn().accepts(arity) {
                                 return self.panic_with(format!(
@@ -1030,11 +1109,19 @@ impl Creature {
                     if self.debug {
                         println!("== returning from {} ==", self.frame.function.show())
                     }
-                    self.frame = self.call_stack.pop().unwrap();
-                    self.ip = self.frame.ip;
                     let mut value = Value::Nothing;
-                    swap(&mut self.return_register[0], &mut value);
-                    self.push(value);
+                    swap(&mut self.register[0], &mut value);
+                    match self.call_stack.pop() {
+                        Some(frame) => {
+                            self.ip = frame.ip;
+                            self.frame = frame;
+                            self.push(value);
+                        }
+                        None => {
+                            self.result = Some(Ok(value));
+                            return;
+                        }
+                    }
                 }
                 Print => {
                     println!("{}", self.pop().show());
diff --git a/src/world.rs b/src/world.rs
index a9db6b2..f44515e 100644
--- a/src/world.rs
+++ b/src/world.rs
@@ -1,3 +1,4 @@
+use crate::chunk::Chunk;
 use crate::value::Value;
 use crate::vm::{Creature, Panic};
 use ran::ran_u8;
@@ -39,12 +40,33 @@ enum Status {
     Nested(Creature),
 }
 
+impl std::fmt::Display for Status {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        match self {
+            Status::Empty => write!(f, "empty"),
+            Status::Borrowed => write!(f, "borrowed"),
+            Status::Nested(creature) => write!(f, "nested {creature}"),
+        }
+    }
+}
+
+impl Status {
+    pub fn receive(&mut self, msg: Value) {
+        match self {
+            Status::Nested(creature) => creature.receive(msg),
+            Status::Borrowed => println!("sending a message to a borrowed process"),
+            Status::Empty => println!("sending a message to a dead process"),
+        }
+    }
+}
+
 #[derive(Debug, Clone, PartialEq)]
-struct Zoo {
+pub struct Zoo {
     procs: Vec<Status>,
     empty: Vec<usize>,
     ids: HashMap<&'static str, usize>,
     dead: Vec<&'static str>,
+    kill_list: Vec<&'static str>,
     active: usize,
 }
 
@@ -54,6 +76,7 @@ impl Zoo {
             procs: vec![],
             empty: vec![],
             ids: HashMap::new(),
+            kill_list: vec![],
             dead: vec![],
             active: 0,
         }
@@ -93,11 +116,17 @@ impl Zoo {
     }
 
     pub fn kill(&mut self, id: &'static str) {
-        if let Some(idx) = self.ids.get(id) {
-            self.procs[*idx] = Status::Empty;
-            self.empty.push(*idx);
-            self.ids.remove(&id);
-            self.dead.push(id);
+        self.kill_list.push(id);
+    }
+
+    pub fn clean_up(&mut self) {
+        while let Some(id) = self.kill_list.pop() {
+            if let Some(idx) = self.ids.get(id) {
+                self.procs[*idx] = Status::Empty;
+                self.empty.push(*idx);
+                self.ids.remove(id);
+                self.dead.push(id);
+            }
         }
     }
 
@@ -125,7 +154,18 @@ impl Zoo {
     }
 
     pub fn next(&mut self, curr_id: &'static str) -> &'static str {
+        println!("getting next process from {curr_id}");
+        println!(
+            "current procs in zoo:\n{}",
+            self.procs
+                .iter()
+                .map(|proc| proc.to_string())
+                .collect::<Vec<_>>()
+                .join("//")
+        );
+        println!("ids: {:?}", self.ids);
         let idx = self.ids.get(curr_id).unwrap();
+        println!("current idx: {idx}");
         if *idx != self.active {
             panic!(
                 "tried to get next creature after {curr_id} while {} is active",
@@ -133,9 +173,14 @@ impl Zoo {
             );
         }
         self.active = (self.active + 1) % self.procs.len();
-        while self.procs[self.active] != Status::Empty {
+        println!("active idx is now: {}", self.active);
+        while self.procs[self.active] == Status::Empty {
+            let new_active_idx = (self.active + 1) % self.procs.len();
+            println!("new active idx: {new_active_idx}");
+            println!("new active process is: {}", self.procs[new_active_idx]);
             self.active = (self.active + 1) % self.procs.len();
         }
+        println!("found next proc: {}", &self.procs[self.active]);
         match &self.procs[self.active] {
             Status::Empty => unreachable!(),
             Status::Borrowed => panic!(
@@ -145,61 +190,63 @@ impl Zoo {
             Status::Nested(proc) => proc.id,
         }
     }
-}
 
-pub type Grasp = Option<Rc<RefCell<World>>>;
+    pub fn send_msg(&mut self, id: &'static str, msg: Value) {
+        let Some(idx) = self.ids.get(id) else {
+            return;
+        };
+        self.procs[*idx].receive(msg);
+    }
+}
 
 #[derive(Debug, Clone, PartialEq)]
 pub struct World {
-    zoo: Zoo,
+    zoo: Rc<RefCell<Zoo>>,
     active: Option<Creature>,
     main: &'static str,
-    handle: Grasp,
     pub result: Option<Result<Value, Panic>>,
 }
 
 impl World {
-    pub fn new(proc: Creature) -> Rc<RefCell<World>> {
-        let mut zoo = Zoo::new();
-        let id = zoo.put(proc);
-        let world = World {
+    pub fn new(chunk: Chunk, debug: bool) -> World {
+        let zoo = Rc::new(RefCell::new(Zoo::new()));
+        let main = Creature::new(chunk, zoo.clone(), debug);
+        let id = zoo.as_ref().borrow_mut().put(main);
+
+        World {
             zoo,
             active: None,
             main: id,
-            handle: None,
             result: None,
-        };
-        let handle = Rc::new(RefCell::new(world));
-        let grasped = handle.clone();
-        let mut world = grasped.as_ref().borrow_mut();
-        world.handle = Some(grasped.clone());
-
-        let mut caught = world.zoo.catch(id);
-        caught.world = world.handle.clone();
-        world.zoo.release(caught);
-
-        handle
+        }
     }
 
-    pub fn spawn(&mut self, proc: Creature) -> Value {
-        let id = self.zoo.put(proc);
-        Value::Keyword(id)
-    }
+    // pub fn spawn(&mut self, proc: Creature) -> Value {
+    //     let id = self.zoo.put(proc);
+    //     Value::Keyword(id)
+    // }
 
-    pub fn send_msg(&mut self, id: &'static str, msg: Value) {
-        let mut proc = self.zoo.catch(id);
-        proc.receive(msg);
-        self.zoo.release(proc);
-    }
+    // pub fn send_msg(&mut self, id: &'static str, msg: Value) {
+    //     let mut proc = self.zoo.catch(id);
+    //     proc.receive(msg);
+    //     self.zoo.release(proc);
+    // }
 
     fn next(&mut self) {
-        let id = self.zoo.next(self.active.as_ref().unwrap().id);
+        let id = self
+            .zoo
+            .as_ref()
+            .borrow_mut()
+            .next(self.active.as_ref().unwrap().id);
+        println!("next id is {id}");
         let mut active = None;
         std::mem::swap(&mut active, &mut self.active);
-        let mut holding_pen = self.zoo.catch(id);
+        let mut holding_pen = self.zoo.as_ref().borrow_mut().catch(id);
         let mut active = active.unwrap();
         std::mem::swap(&mut active, &mut holding_pen);
-        self.zoo.release(holding_pen);
+        println!("now in the holding pen: {}", holding_pen.id);
+        holding_pen.reset_reductions();
+        self.zoo.as_ref().borrow_mut().release(holding_pen);
         let mut active = Some(active);
         std::mem::swap(&mut active, &mut self.active);
     }
@@ -234,22 +281,47 @@ impl World {
     //     self.next(id);
     // }
 
-    pub fn run(&mut self) {
-        let main = self.zoo.catch(self.main);
+    pub fn activate_main(&mut self) {
+        let main = self.zoo.as_ref().borrow_mut().catch(self.main);
         self.active = Some(main);
+    }
+
+    pub fn active_id(&mut self) -> &'static str {
+        self.active.as_ref().unwrap().id
+    }
+
+    pub fn kill_active(&mut self) {
+        let id = self.active_id();
+        self.zoo.as_ref().borrow_mut().kill(id);
+    }
+
+    pub fn active_result(&mut self) -> &Option<Result<Value, Panic>> {
+        &self.active.as_ref().unwrap().result
+    }
+
+    pub fn clean_up(&mut self) {
+        self.zoo.as_ref().borrow_mut().clean_up()
+    }
+
+    pub fn run(&mut self) {
+        self.activate_main();
         loop {
+            println!("entering world loop");
             self.active.as_mut().unwrap().interpret();
-            match self.active.as_ref().unwrap().result {
+            println!("interpreted loop");
+            match self.active_result() {
                 None => (),
                 Some(_) => {
-                    if self.active.as_ref().unwrap().id == self.main {
-                        self.result = self.active.as_ref().unwrap().result.clone();
+                    if self.active_id() == self.main {
+                        self.result = self.active_result().clone();
                         return;
                     }
-                    self.zoo.kill(self.active.as_ref().unwrap().id);
+                    self.kill_active();
                 }
             }
+            println!("getting next process");
             self.next();
+            self.clean_up();
         }
     }