Set hollow_knob parameter to true to make knobs hollow.
Set circular_hole parameter to true to make circular holes like in standard Technic plates.
Set flat_top parameter to true to get rid of the knobs and add a groove to the bottom, so that the blocks could be separated.

Set reinforcement to false if you want to make 1xN or Nx1 bricks without pins. Set it to true to have pins. The meaning remains the same for other sizes.

EXAMPLES:

standard LEGO 2x1 tile without pin
block(1,2,1/3,reinforcement=false,flat_top=true);
standard LEGO 2x1 flat with pin
block(1,2,1/3,reinforcement=true);
standard LEGO 2x1 brick with pin
block(1,2,1,reinforcement=true);
standard LEGO 2x1 brick without pin
block(1,2,1,reinforcement=false);
standard LEGO 2x1x5 brick has no pin and has hollow knobs
block(1,2,5,reinforcement=false,hollow_knob=true);