Newton's cradle

This thing is desinged to be a toy called a Newton's crade. What you do is you lift up a ball at one end, and the ball on the other end will recive the energy from the ball you lifted up, while the three in the middle don't move! There are other tricks you can do with this, such as lifting up two balls and two balls will recive the momentum. If you are going to print this, look at the instructions for how to print! If you don't follow them, this toy won't work. This thing was made in Open SCAD in two parts. The first one was the cradle. The code for that is below:
cube([50,45,5]);
difference() {
cube([50,5,50]);
translate([5,0,0])cube([40,5,45]);
translate([5,0,47])rotate([-90,0,0])cylinder(45,1,1,$fn=100);
translate([15,0,47])rotate([-90,0,0])cylinder(45,1,1,$fn=100);
translate([25,0,47])rotate([-90,0,0])cylinder(45,1,1,$fn=100);
translate([35,0,47])rotate([-90,0,0])cylinder(45,1,1,$fn=100);
translate([45,0,47])rotate([-90,0,0])cylinder(45,1,1,$fn=100);
translate([