manual

You need:
13
How to do it:
1) Lay the cardboard arms apart
on a completely flat surface,
as in the diagram.
2) Rest the cylinder on the
midpoint of the arms and
it will roll down toward
the lower part of the
arms, as you’d expect!
star
ting
point
cardboard arms
cylinder
plastic double cone
starting point
3) Rest the double cone on
the midpoint of the ar
ms
and it will roll toward the
upper part of the arms.
Surprise! It goes uphill,
but how?