|Falling Rock signs and Children's signs in Japan are made following the same procedures : check the design of other countries and then make your own mix.
The shape of the panel is taken from the Americas. The colour choice and the presence of a borderline also. But take a closer look at the
corners: they are only round at the inside. Corners in the U.S.A are rounded at both sides. (more examples: Argentina, Chile)
The configuration of the boulders is copied from Pakistan : the same number of boulders, the top rock
in a cavity in the wall and the same speed indicators. The shape of the
boulders was adapted to make them look more natural. It's difficult though
to believe that the rock on the ground rests in equilibrium.