We have reason to believe that Galileo did three variations on studying the motion of projectiles. In the first he rolled an inked ball down an inclined plane, letting it roll down a deflector, off a table, then hit the floor. The second variation is the same as the first except that the deflector is removed and the ball travels from the inclined plane to the floor.  The last variation is that the horizontal plane (normally what would be the floor) was placed at different heights to trace the path the projectile takes. 
We replicated the second and third variations. We did not reproduce the first because the ball would not roll on the deflector because the angles we were working with were too small.