diff --git a/attachments.scad b/attachments.scad
index d0e37be..4a9416e 100644
--- a/attachments.scad
+++ b/attachments.scad
@@ -2978,7 +2978,7 @@ module attachable(
         assert(is_undef(anchor) || is_vector(anchor) || is_string(anchor), str("Invalid anchor: ",anchor))
         assert(is_undef(spin) || is_finite(spin), str("Invalid spin: ",spin))
         assert(is_undef(orient) || is_vector(orient,3), str("Invalid orient: ",orient));
-        assert(in_list(axis,[UP,RIGHT,BACK]), "axis must be a positive coordinate direction, either UP, BACK or RIGHT");
+        assert(in_list(v_abs(axis),[UP,RIGHT,BACK]), "axis must be a coordinate direction");
     anchor = default(anchor,CENTER);
     spin = default(spin,0); 
     orient = is_def($anchor_override)? UP : default(orient, UP);
diff --git a/tutorials/Shapes3d.md b/tutorials/Shapes3d.md
index 4aa924b..8ff179e 100644
--- a/tutorials/Shapes3d.md
+++ b/tutorials/Shapes3d.md
@@ -47,22 +47,13 @@ include <BOSL2/std.scad>
 cube([50,40,20], anchor=TOP+FRONT+LEFT);
 ```
 
-You can use `spin=` to rotate around the Z axis:
+You can use `spin=` to rotate around the Z axis **after** anchoring:
 
 ```openscad-3D
 include <BOSL2/std.scad>
 cube([50,40,20], anchor=FRONT, spin=30);
 ```
 
-3D objects also gain the ability to use an extra trick with `spin=`;
-if you pass a list of `[X,Y,Z]` rotation angles to `spin=`, it will
-rotate by the three given axis angles, similar to using `rotate()`:
-
-```openscad-3D
-include <BOSL2/std.scad>
-cube([50,40,20], anchor=FRONT, spin=[15,0,30]);
-```
-
 3D objects also can be given an `orient=` argument as a vector, pointing
 to where the top of the shape should be rotated towards.