diff --git a/app-proto/src/add_remove.rs b/app-proto/src/add_remove.rs
index 448119b..0e60a1f 100644
--- a/app-proto/src/add_remove.rs
+++ b/app-proto/src/add_remove.rs
@@ -299,9 +299,11 @@ fn load_irisawa_hexlet_assemb(assembly: &Assembly) {
     assembly.insert_regulator(Rc::new(outer_moon_tangency));
 }
 
-// setting the inversive distances between the vertices to -2 gives a
-// regular tetrahedron with side length 1, whose insphere and circumsphere have
-// radii sqrt(1/6) and sqrt(3/2), respectively
+// setting the inversive distances between the vertices to -2 gives a regular
+// tetrahedron with side length 1, whose insphere and circumsphere have radii
+// sqrt(1/6) and sqrt(3/2), respectively. to measure those radii, set an
+// inversive distance of -1 between the insphere and each face, and then set an
+// inversive distance of 0 between the circumsphere and each vertex
 fn load_radius_ratio_assemb(assembly: &Assembly) {
     let index_range = 1..=4;