A Post-it note (or just Post-it), manufactured by 3M, is a piece of stationery with a readherable strip of adhesive on the back, designed for temporarily attaching notes to documents, computer displays and so forth. ~ from Wikipedia
These sketches were just done quickly on Post-It pads so I would have something appropriate to put on the blog. We actually do alot of design brainstorming on Post-Its at work, but they are less interesting. Maybe I'll grab a few of those sometime, but they are of bottles and packages mostly.