parallel.rb

# process based .. has memory implication


sleep_time = 10

pids= []

10.times do |n|
 pids << fork do
  sleep sleep_time
 end
 sleep_time += 10
end
# not exactly parallel,, this will halt the execution till the pid returns (im sure Process class has some async api, to get around this) 
pids.each do |pid|
  Process.waitpid(pid)
end

# thread based
sleep_time = 10
threads = []
10.times do |n|
 threads << Thread.new do
  sleep sleep_time
 end
 sleep_time += 10
end

pids.each do |thread|
  thread.join
end