$fn = 50;
/* eprouvette de traction minimaliste */
difference() {
    translate([0,0,25]) cube([10,10,50], center = true);
    translate([0,0,5]) rotate([0,90,0]) cylinder(h = 12, r = 2.5, center = true);
    translate([0,0,45]) rotate([0,90,0]) cylinder(h = 12, r = 2.5, center = true);
}