DRAW GRID, DRAW AXES (original enhancement) ☆☆☆

Original Enhancement
DRAW GRID
draws a grid with gaps of 1 unit.
DRAW GRID(p,q)
draws a grid with horizontal gaps p, vertical gaps q.
DRAW AXES
draws x-axis and y-axis with ticks
DRAW AXES(p,q)
draws x-axis with ticks of interval p, y-axis with ticks of interval q.
DRAW GRID0
DRAW AXES0
Draws a grid or axes without numeric labels.

Supplied DRAW statements mentioned above use the color of index 15.