Daniel Shiffman has recently published the second edition of his Learning Processing book updated for processing-3.0. He has also published the code here. This a port of his mouse history sketch, which makes use of ruby Struct instead of PVector and ruby Array in place of ArrayList. Show your ruby chops by porting some more examples…

And send me a tweet @monkstoneT

Here is the sketch code:-

# Learning Processing
# Daniel Shiffman
# https://www.learningprocessing.com

# Example 23-5: A snake following the mouse Using an Array
# of Struct (we just need something to hold x and y values)

Vect = Struct.new(:x, :y)

attr_reader :history

def setup
  sketch_title 'Mouse History'
  @history = []

def draw
  # New mouse position
  history << Vect.new(mouse_x, mouse_y)
  # Remove old ones
  history.shift if history.size > 50
  # Draw everything
  history.each_with_index do |vec, i|
    # Draw an ellipse for each element of the Array.
    fill(255 - i * 5)
    ellipse(vec.x, vec.y, i, i)

def settings
  size 300, 300

I have also ported The Nature of Code to JRubyArt.