use minkowski? as another density function

src/shimmers/math/equations.cljc

@@ -210,3 +210,17 @@
 
 (comment (map (fn [x] (stair-sigmoid 0.1 10.0 0 1 x))
               (range 0 1 (/ 1.0 30))))
+
+;; https://en.wikipedia.org/wiki/Minkowski%27s_question-mark_function
+;; https://rosettacode.org/wiki/Minkowski_question-mark_function#Julia
+(defn minkowski? [^double x]
+  (loop [p (mod x 1.0) q (- 1.0 x) y (quot x 1.0) d 0.5]
+    (if (> (+ y d) y)
+      (if (< p q)
+        (recur p (- q p) y (/ d 2.0))
+        (recur (- p q) q (+ y d) (/ d 2.0)))
+      y)))
+
+(comment
+  (for [x (range 0 1 0.02)]
+    [x (minkowski? x)]))

src/shimmers/sketches/cilia_phase.cljs

@@ -95,7 +95,8 @@
                            :random-normal 0.66
                            :stripes 1.33
                            :sin-stripes 1.0
-                           :stair-sigmoid 2.0})
+                           :stair-sigmoid 2.0
+                           :minkowski 1.33})
         proportion
         (dr/weighted {6 1.0
                       5.0 1.0
@@ -127,6 +128,9 @@
         :alpha (dr/random 1.0 3.0)
         :rate (* 2.5 (dr/happensity 0.4))
         :amp (dr/weighted {0.05 1.0 0.075 1.0 0.025 1.0 0.1 0.5})}
+       :minkowski
+       {:amp (dr/random 0.05 0.25)
+        :rate (dr/random 1.0 4.0)}
        {}))))
 
 (defn samples-from-density [{:keys [mode density] :as pts}]
@@ -157,7 +161,12 @@
     (let [{:keys [freq alpha rate amp]} pts]
       (for [x (range -0.05 1.05 (/ 1.0 density))]
         (eq/stair-sigmoid (/ 1.0 freq) freq 0 alpha
-                          (+ x (* amp (eq/sin-tau (* rate x)))))))))
+                          (+ x (* amp (eq/sin-tau (* rate x)))))))
+    :minkowski
+    (let [{:keys [amp rate]} pts]
+      (for [x (range -0.05 1.05 (/ 1.0 (* 1.2 density)))]
+        (+ (eq/minkowski? x)
+           (* amp (eq/sin-tau (+ (* rate x)))))))))
 
 (defn line-parameters []
   (let [n (dr/weighted {(dr/random-int 3 8) 6.0