The Scratch Stretch block existed in older versions of Scratch but was removed. That's too bad because it is a lot of fun to use in projects. Please let the Scratch Team know if you would like them to add it back into Scratch. The code you see will work in Scratch 0.2 and the stick man will move smoothly instead of the jerky movement in this simulation
The music is a violin duet version of Bach's Bourree in E minor. This version is from "Best of Bach for violin duet" by Mark Phillips. I am playing both parts on my violin. Update: A working Stretch block was actually part of Scratch 1.x but was not included in the block palette. However, a person could start with a Scratch 0.x project with a Stretch block and load it into the Scratch 1.x editor.