diff --git a/prelude.md b/prelude.md
index 7148451..d569b5e 100644
--- a/prelude.md
+++ b/prelude.md
@@ -12,6 +12,24 @@ or they are variations on a function, e.g. `div/0` as a variation on `div`.
 
 **How entries are formatted.** Each entry has a brief (sometimes too brief!) description of what it does.
 It is followed by the patterns for each of its function clauses.
+This should be enough to indicate order of arguments, types, and so on.
+
+**Patterns often, but do not always, indicate types.** Typed patterns are written as `foo as :bar`,
+where the type is indicated by the keyword. 
+Possible ludus types are: `:nil`, `:boolean`, `:number`, `:keyword` (atomic values);
+`:string` (strings are their own beast); `:tuple` and `:list` (indexed collections); `:set` (sets are specific), 
+`:dict` and `:ns` (associative collections); and `:ref` (references).
+
+**Conventional types.** Ludus has two types based on conventions.
+* _Result tuples._ Results are a way of modeling the result of a calculation that might fail.
+The two possible values are `(:ok, value)` and `(:err, msg)`.
+`msg` is usually a string describing what went wrong.
+To work with result tuples, see [`unwrap!`](#unwrap) and [`unwrap_or`](#unwrap_or).
+That said, usually you work with these using pattern matching.
+
+* _Vectors._ Vectors are 2-element tuples of x and y coordinates.
+The origin is `(0, 0)`. 
+`add` and `mult` can take vectors as well as numbers.
 
 [abs](#abs)&nbsp;&nbsp;&nbsp; [add](#add)&nbsp;&nbsp;&nbsp; [and](#and)&nbsp;&nbsp;&nbsp; [angle](#angle)&nbsp;&nbsp;&nbsp; [append](#append)&nbsp;&nbsp;&nbsp; [assert!](#assert)&nbsp;&nbsp;&nbsp; [assoc](#assoc)&nbsp;&nbsp;&nbsp; [assoc?](#assoc)&nbsp;&nbsp;&nbsp; [at](#at)&nbsp;&nbsp;&nbsp; [atan/2](#atan/2)&nbsp;&nbsp;&nbsp; [back!](#back)&nbsp;&nbsp;&nbsp; [background!](#background)&nbsp;&nbsp;&nbsp; [bg!](#bg)&nbsp;&nbsp;&nbsp; [bgcolor](#bgcolor)&nbsp;&nbsp;&nbsp; [bk!](#bk)&nbsp;&nbsp;&nbsp; [bool](#bool)&nbsp;&nbsp;&nbsp; [bool?](#bool)&nbsp;&nbsp;&nbsp; [butlast](#butlast)&nbsp;&nbsp;&nbsp; [ceil](#ceil)&nbsp;&nbsp;&nbsp; [clear!](#clear)&nbsp;&nbsp;&nbsp; [coll?](#coll)&nbsp;&nbsp;&nbsp; [colors](#colors)&nbsp;&nbsp;&nbsp; [concat](#concat)&nbsp;&nbsp;&nbsp; [console](#console)&nbsp;&nbsp;&nbsp; [cos](#cos)&nbsp;&nbsp;&nbsp; [count](#count)&nbsp;&nbsp;&nbsp; [dec](#dec)&nbsp;&nbsp;&nbsp; [deg/rad](#deg/rad)&nbsp;&nbsp;&nbsp; [deg/turn](#deg/turn)&nbsp;&nbsp;&nbsp; [deref](#deref)&nbsp;&nbsp;&nbsp; [dict](#dict)&nbsp;&nbsp;&nbsp; [diff](#diff)&nbsp;&nbsp;&nbsp; [dissoc](#dissoc)&nbsp;&nbsp;&nbsp; [dist](#dist)&nbsp;&nbsp;&nbsp; [div](#div)&nbsp;&nbsp;&nbsp; [div/0](#div/0)&nbsp;&nbsp;&nbsp; [div/safe](#div/safe)&nbsp;&nbsp;&nbsp; [doc!](#doc)&nbsp;&nbsp;&nbsp; [each!](#each)&nbsp;&nbsp;&nbsp; [eq?](#eq)&nbsp;&nbsp;&nbsp; [err](#err)&nbsp;&nbsp;&nbsp; [err?](#err)&nbsp;&nbsp;&nbsp; [even?](#even)&nbsp;&nbsp;&nbsp; [false?](#false)&nbsp;&nbsp;&nbsp; [fd!](#fd)&nbsp;&nbsp;&nbsp; [first](#first)&nbsp;&nbsp;&nbsp; [floor](#floor)&nbsp;&nbsp;&nbsp; [flush!](#flush)&nbsp;&nbsp;&nbsp; [fn?](#fn)&nbsp;&nbsp;&nbsp; [fold](#fold)&nbsp;&nbsp;&nbsp; [forward!](#forward)&nbsp;&nbsp;&nbsp; [get](#get)&nbsp;&nbsp;&nbsp; [goto!](#goto)&nbsp;&nbsp;&nbsp; [gt?](#gt)&nbsp;&nbsp;&nbsp; [gte?](#gte)&nbsp;&nbsp;&nbsp; [heading](#heading)&nbsp;&nbsp;&nbsp; [heading/vector](#heading/vector)&nbsp;&nbsp;&nbsp; [home!](#home)&nbsp;&nbsp;&nbsp; [inc](#inc)&nbsp;&nbsp;&nbsp; [join](#join)&nbsp;&nbsp;&nbsp; [keys](#keys)&nbsp;&nbsp;&nbsp; [keyword?](#keyword)&nbsp;&nbsp;&nbsp; [last](#last)&nbsp;&nbsp;&nbsp; [left!](#left)&nbsp;&nbsp;&nbsp; [list](#list)&nbsp;&nbsp;&nbsp; [lt!](#lt)&nbsp;&nbsp;&nbsp; [lt?](#lt)&nbsp;&nbsp;&nbsp; [lte?](#lte)&nbsp;&nbsp;&nbsp; [make!](#make)&nbsp;&nbsp;&nbsp; [map](#map)&nbsp;&nbsp;&nbsp; [mod](#mod)&nbsp;&nbsp;&nbsp; [mult](#mult)&nbsp;&nbsp;&nbsp; [neg](#neg)&nbsp;&nbsp;&nbsp; [neg?](#neg)&nbsp;&nbsp;&nbsp; [nil?](#nil)&nbsp;&nbsp;&nbsp; [not](#not)&nbsp;&nbsp;&nbsp; [odd?](#odd)&nbsp;&nbsp;&nbsp; [ok](#ok)&nbsp;&nbsp;&nbsp; [ok?](#ok)&nbsp;&nbsp;&nbsp; [or](#or)&nbsp;&nbsp;&nbsp; [ordered?](#ordered)&nbsp;&nbsp;&nbsp; [p5_calls](#p5_calls)&nbsp;&nbsp;&nbsp; [panic!](#panic)&nbsp;&nbsp;&nbsp; [pc!](#pc)&nbsp;&nbsp;&nbsp; [pd!](#pd)&nbsp;&nbsp;&nbsp; [pencolor](#pencolor)&nbsp;&nbsp;&nbsp; [pencolor!](#pencolor)&nbsp;&nbsp;&nbsp; [pendown!](#pendown)&nbsp;&nbsp;&nbsp; [pendown?](#pendown)&nbsp;&nbsp;&nbsp; [penup!](#penup)&nbsp;&nbsp;&nbsp; [penwidth](#penwidth)&nbsp;&nbsp;&nbsp; [penwidth!](#penwidth)&nbsp;&nbsp;&nbsp; [pi](#pi)&nbsp;&nbsp;&nbsp; [pos?](#pos)&nbsp;&nbsp;&nbsp; [position](#position)&nbsp;&nbsp;&nbsp; [print!](#print)&nbsp;&nbsp;&nbsp; [prn!](#prn)&nbsp;&nbsp;&nbsp; [pu!](#pu)&nbsp;&nbsp;&nbsp; [pw!](#pw)&nbsp;&nbsp;&nbsp; [rad/deg](#rad/deg)&nbsp;&nbsp;&nbsp; [rad/turn](#rad/turn)&nbsp;&nbsp;&nbsp; [random](#random)&nbsp;&nbsp;&nbsp; [range](#range)&nbsp;&nbsp;&nbsp; [render_turtle!](#render_turtle)&nbsp;&nbsp;&nbsp; [report!](#report)&nbsp;&nbsp;&nbsp; [reset_turtle!](#reset_turtle)&nbsp;&nbsp;&nbsp; [rest](#rest)&nbsp;&nbsp;&nbsp; [right!](#right)&nbsp;&nbsp;&nbsp; [round](#round)&nbsp;&nbsp;&nbsp; [rt!](#rt)&nbsp;&nbsp;&nbsp; [second](#second)&nbsp;&nbsp;&nbsp; [set](#set)&nbsp;&nbsp;&nbsp; [show](#show)&nbsp;&nbsp;&nbsp; [sin](#sin)&nbsp;&nbsp;&nbsp; [slice](#slice)&nbsp;&nbsp;&nbsp; [some](#some)&nbsp;&nbsp;&nbsp; [some?](#some)&nbsp;&nbsp;&nbsp; [square](#square)&nbsp;&nbsp;&nbsp; [string](#string)&nbsp;&nbsp;&nbsp; [string?](#string)&nbsp;&nbsp;&nbsp; [sub](#sub)&nbsp;&nbsp;&nbsp; [sum_of_squares](#sum_of_squares)&nbsp;&nbsp;&nbsp; [tan](#tan)&nbsp;&nbsp;&nbsp; [tau](#tau)&nbsp;&nbsp;&nbsp; [turn/deg](#turn/deg)&nbsp;&nbsp;&nbsp; [turn/rad](#turn/rad)&nbsp;&nbsp;&nbsp; [turtle_commands](#turtle_commands)&nbsp;&nbsp;&nbsp; [turtle_state](#turtle_state)&nbsp;&nbsp;&nbsp; [turtle_states](#turtle_states)&nbsp;&nbsp;&nbsp; [type](#type)&nbsp;&nbsp;&nbsp; [unwrap!](#unwrap)&nbsp;&nbsp;&nbsp; [unwrap_or](#unwrap_or)&nbsp;&nbsp;&nbsp; [update](#update)&nbsp;&nbsp;&nbsp; [update!](#update)&nbsp;&nbsp;&nbsp; [values](#values)&nbsp;&nbsp;&nbsp; [zero?](#zero)
 ## Function documentation
diff --git a/target/repl-port b/target/repl-port
deleted file mode 100644
index 7ab7009..0000000
--- a/target/repl-port
+++ /dev/null
@@ -1 +0,0 @@
-54180
\ No newline at end of file