*Items are in the BlocklyProp Starter Kit [6]. ** The BlocklyProp Starter Kit has just one servo, get another servo here [4].
CAUTION! Don't try to run this project off of your computer's USB power alone - use the battery pack too. The servos can take quite a bit of current when they move, and may exceed the amount of current that your USB port can supply.
Links
[1] http://www.parallax.com/product/32912
[2] http://www.parallax.com/product/28380
[3] http://www.parallax.com/product/800-00080
[4] http://www.parallax.com/product/900-00005
[5] http://www.parallax.com/product/753-00007
[6] http://www.parallax.com/product/32520