I wacked them with a hammer, a lot. Watch the videos. the first picture is the arc, the second is the ball thing.
Step 2: How to make
This is easy. Take tissues toilet paper ect. roll them into some kind of cylinder or ball, if you want pykrete like the arc don't squeez the water out, if you want the other kind squeez out as much water as you can, i have a video showing their strength on the next page.