If you combine a when space pressed block with an erase all block, then when you hit the space bar you would erase any drawings created by your program.

  to change the number of rows and columns displayed by the excel object a. select the object and drag a size handle on the active object. b. deselect the object and drag a size handle of the object. c. deselect the object and drag a row or column divider of the object. d. select the object and drag a row or column divider on the active object.