tetrahedron
-has been given a short anchor base ontop of the four triangles
-is light,  enough to be rottated and carried by a good robot
-made of soft rubber-type material to be easily griped by the robot's claw

hoop
-light in weight
-thin cross-section
-huge diametor

1.One hoop going out of the field equals 0.5 points lost and can not be brought back.

2.The validity of a tetrahedron outside the field is 20 seconds before its counted off the game.

3.The time taken to shoot all hoops is considered while choosing the winner so one shoot do all activities in the shortest time possible.