Rotate logic gate sprites based on direction.

modules/math.scm

@@ -19,15 +19,15 @@
 ;;; Code:
 
 (define-module (math)
-  #:pure
-  #:use-module (scheme base)
   #:use-module (hoot ffi)
-  #:export (random clamp))
+  #:export (random pi clamp))
 
 (define-foreign random
   "math" "random"
   -> f64)
 
+(define pi (* 4.0 (atan 1.0)))
+
 (define (clamp x min max)
   (cond ((< x min) min)
         ((> x max) max)