diff --git a/ch_1_intro.md b/ch_1_intro.md
index ef3c361..47e7b06 100644
--- a/ch_1_intro.md
+++ b/ch_1_intro.md
@@ -587,7 +587,7 @@ Having put `spingon!` into motion, how do you make it stop at a stage of your ch
 You need to have a way of telling it how to stop.
 That's another characteristic to include as an argument.
 Look at the following modification to `spingon!`.
-Review the conditional commands in Ludus.
+Review the conditional forms in Ludus.
 `if ::something:: then ::something:: else ::something::` is such a conditional. 
 Using the `if` form, everything becomes very tidy.
 
@@ -598,7 +598,7 @@ fn spingon! (n, edge, angle, growth, times) -> {
   & This is the conditional stopper.
   else {
     ngon! (n, edge)
-    rt! (angle)
+    right! (angle)
     spingon! (n, mult (edge, growth), angle, growth, dec (times))
     & Note the new argument above.
   }
@@ -676,7 +676,7 @@ Consult your own Ludus manual for handling the problem of function layout.
 ### Exercises
 There are five exercises to explore before going on to the material of chapter 2.
 The first is so important that we will go through it together, step by step.
-You can work on the other exercisesby yourself.
+You can work on the other exercises by yourself.
 
 #### Exercise 1.1
 Make `ngon!` more versatile by doing two things to it.
@@ -790,7 +790,7 @@ The two amounts, `angle` and `edge`, are still unknown.
 To figure these bits will require a little geometry and trigonometry.
 We might as well use this opportunity to review all the bits and pieces of polygons.
 
-### The Geometry of CNGONs
+### The Geometry of `cngon`s
 Use the following two diagrams in conjunction with the word and equation descriptions.
 
 {{Figure 11: Geometry of `cngon`s. Bottom of p. 28.}}