num and numDist can be integer constants, or integer variables. Floating-point values are obviously illegal; creating 2.71828 lines is meaningless. Using a floating-point constant or variable will cause a crash. Leaving out a parameter causes a run-time crash.

createLines() creates num lines, plus or minus numDist lines. All attributes that are currently active are applied to all lines created. If you want the same number of lines created every time, numDist should be zero. Otherwise, you'll end up with somewhere between (num + numDist) and (num - numDist) lines.