board_width = 70;
board_height = 50;
thickness = 1.45;
insert_width = 45;
insert_depth = 12;

hole_vdist = 44.5;
hole_hdist = 65;
hole_diameter = 2;
hole_radius = hole_diameter / 2;
hole_margin = 1;

top_margin = (board_height - hole_vdist) / 2 + hole_diameter + hole_margin*2;
side_margin = (board_width - hole_hdist) / 2 + hole_diameter + hole_margin*2;

cutout_width = board_width - (side_margin * 2);
cutout_height = board_height - (top_margin * 2);

hole_horiz = (board_width - hole_hdist) / 2;
hole_vert = (board_height - hole_vdist) / 2;

standoff_radius = hole_radius * 2.5;
standoff_height = 3;


difference() {
        union() {
            cube([board_width, board_height, thickness]);
            linear_extrude(thickness)
            polygon([[0,0], [(board_width-insert_width)/2, -insert_depth], [board_width-(board_width-insert_width)/2, -insert_depth], [board_width, 0]]);

        translate([hole_horiz, hole_vert, 0])
        cylinder(thickness+standoff_height, r=standoff_radius, $fn=360);

        translate([board_width - hole_horiz, hole_vert, 0])
        cylinder(thickness+standoff_height, r=standoff_radius, $fn=360);

        translate([hole_horiz, board_height - hole_vert, 0])
        cylinder(h=thickness+standoff_height, r=standoff_radius, $fn=360);

        translate([board_width - hole_horiz, board_height - hole_vert, 0])
        cylinder(h=thickness+standoff_height, r=standoff_radius, $fn=360);


    }

    translate([side_margin, top_margin, -1])
    cube([cutout_width, cutout_height, thickness+3]);
    
    translate([hole_horiz, hole_vert, -1])
    cylinder(h=thickness+standoff_height+3, r=hole_radius, $fn=360);

    translate([board_width - hole_horiz, hole_vert, -1])
    cylinder(h=thickness+standoff_height+3, r=hole_radius, $fn=360);

    translate([hole_horiz, board_height - hole_vert, -1])
    cylinder(h=thickness+standoff_height+3, r=hole_radius, $fn=360);

    translate([board_width - hole_horiz, board_height - hole_vert, -1])
    cylinder(h=thickness+standoff_height+3, r=hole_radius, $fn=360);


}
