You might have a look at Scratch, a visual programming environment for kids. You plug variables and programming constructs together.

http://scratch.mit.edu/

Here's my Towers of Hanoi from a few years ago. It runs on Windows Firefox, but I can't get it to run on Linux Firefox or Chrome; Scratch and Linux's Java plugin must have parted ways in the intervening years.

http://scratch.mit.edu/projects/nfnaaron/93232