About this 3D model

I am just learning about OpenSCAD (my 1st day with it today). I was thinking a great test piece to print out when I get and assemble my MakerBot kit in a month, would be a ruler sized to the stage limits. The large marks should be centimeters and the smaller marks millimeters. The minimum resolution I used was 0.2 mm. Sorry but I do not know yet how to put letters or numbers on it yet.I can not wait to test this print. I expect (if it works) I will go around the house with it to eyeball things I could print out. Also, it will be good since I can never find a ruler or straight edge when I need it.