#!/usr/bin/env ruby lines = File.read("palette.ppm").split("\n") lines = lines.select { |l| l[0] != "#" } raise "Not an ASCII ppm" if lines.shift != "P3" raise "Incorrect dimensions" unless lines.shift == "1 256" raise "Incorrect maxval" unless lines.shift == "255" raise "Too many lines left" unless lines.size == 768 puts <