// toolpath offsetting example
$fn=30;
// using minkowski (tracing a shape with a shape)
translate([0,0,2])color("red")minkowski(){
    cube([30,30,1]);
    cylinder(d=5,h=1);
}
cube([30,30,6]);
color("grey")translate([0,-2.5])cylinder(d=5,h=10);
translate([40,0,0]){
    translate([0,0,2])color("red")offset(r=2.5)projection(){
    cube([30,30,1]);
    }
// using the 2D offset function
    color("green")translate([0,0,6])offset(r=-2.5,chamfer = true)projection(){
        cube([30,30,1]);
    }
    cube([30,30,6]);
    color("grey")translate([0,-2.5,0])cylinder(d=5,h=10);
    color("grey")translate([2.5,25,0])cylinder(d=5,h=10);
}