depth = 1.2;
height = 3;
hole = 3.5;
thickness = 0.6;
width = 4;

//*
// corner
translate([3.5, 0, 0]) cube([width, 3.5, thickness]);
translate([3.5, 3.5, 0]) cube([width, width, thickness]);
translate([0, 3.5, 0]) cube([3.5, width, thickness]);
translate([-depth, 3.5, 0]) cube([depth, width, height]);
translate([3.5, -depth, 0]) cube([width, depth, height]);
/*/
// inline
translate([hole, 0, 0]) cube([width, hole, thickness]);
translate([hole, hole, 0]) cube([width, width, thickness]);
translate([0, hole, 0]) cube([hole, width, thickness]);
translate([-width, hole, 0]) cube([width, width, thickness]);
translate([-width, 0, 0]) cube([width, hole, thickness]);
translate([-width, -depth, 0]) cube([width, depth, height]);
translate([hole, -depth, 0]) cube([width, depth, height]);
//*/