overhaul operator precedence

arithmetic operators now have the same precedence.
if you want them to bind tighter, you remove the spaces around them:

- 2 + 2 * 2 = 8
- 2 + 2*2 = 6

static/brush-box.js

@@ -76,9 +76,9 @@ wavelength: 1
 
 withDotter \\d ->
   pi = 3.14159265
-  a = (sin (d Num * wavelength / pi) + 1) / 2
+  a = sin (d Num * wavelength / pi) + 1 / 2
   range = maxThickness - minThickness
-  thickness = minThickness + a * range
+  thickness = a * range + minThickness
   stroke thickness color (line (d From) (d To))
         `.trim(),
     },