$fn = 50;
/* eprouvette de traction - version 2 */

L = 70;
module forme() {
    union() {
        offset(r = -2) offset(delta = 2){
            translate([0,0]) square([4,L], center = true);
            translate([0,L/2]) square([15,15], center = true);
            translate([0,-L/2]) square([15,15], center = true);
        }
    }
}

linear_extrude(4) difference() {
    forme();
    translate([0,L/2]) circle(d = 3);
    translate([0,-L/2]) circle(d = 3);
}