Add a little ASCII art Mandelbrot example.

example/mandelbrot.wren

@@ -0,0 +1,36 @@
+var yMin = -0.2
+var yMax = 0.1
+var xMin = -1.5
+var xMax = -1.1
+
+for (yPixel in 0...24) {
+  var y = (yPixel / 24) * (yMax - yMin) + yMin
+  for (xPixel in 0...80) {
+    var x = (xPixel / 79) * (xMax - xMin) + xMin
+    var pixel = " "
+    var x0 = x
+    var y0 = y
+    for (iter in 0...80) {
+      var x1 = (x0 * x0) - (y0 * y0)
+      var y1 = 2 * x0 * y0
+
+      // Add the seed.
+      x1 = x1 + x
+      y1 = y1 + y
+
+      x0 = x1
+      y0 = y1
+
+      // Stop if the point escaped.
+      var d = (x0 * x0) + (y0 * y0)
+      if (d > 4) {
+        pixel = " .:;+=xX$&"[(iter / 8).floor]
+        break
+      }
+    }
+
+    IO.write(pixel)
+  }
+
+  IO.print("")
+}