bitmap(int x, int y, string bits) - draw a bitmap at (x,y). The bits string is a list of hexadecimal digits in the following form: "wwxxxxxxxx..." where 'ww' is the width of the bitmap (i.e. '0a' is a 10-pixel wide bitmap), and 'xxx...' are the bits of the bitmap, each character representing 4 pixels. So, "0affc804804ffc" is a 10x4 bitmap of a rectangle ('ffc' is a solid line, '804' represents a left and right edge.)
Example:
A 10x4 rectangle "0affc804804ffc"
8 4 2 1 8 4 2 1 8 4 2 1
X X X X X X X X X X 0 0 = ffc
X 0 0 0 0 0 0 0 0 X 0 0 = 804
X 0 0 0 0 0 0 0 0 X 0 0 = 804
X X X X X X X X X X 0 0 = ffc
A small square (5x5) with a dot in the center would be "05f888a888f8"
8 4 2 1 8 4 2 1
X X X X X 0 0 0 = f8
X 0 0 0 X 0 0 0 = 88
X 0 X 0 X 0 0 0 = a8
X 0 0 0 X 0 0 0 = 88
X X X X X 0 0 0 = f8