Four Square in the Air / Volleyball Four-Square

Volleyball Four-Square, AKA "four square in the air", is an exciting combination of four-square and volleyball. It requires the creation of four three-dimensional 'cells', open at the tops but clearly delineated. This Thing assumes you will build the frame from 40mm plastic drainpipe, and provides friction-fit fixings to assemble them into the three-dimensional structure. The friction fit makes it quick and easy to assemble and pack away.

#How To Play#
These are our 'house rules', you may wish to fine-tune for your setting. Consider this 'top down' diagram:

Each 'square' is numbered 1-4. One player stands in each square, the player in Square 1 is the king/queen. If you have more than four players, we set out a chair for each extra - numbered 4, 5, 6 etc.

The 'king' serves the ball up through the top of their square, and it must come down through any other player's square. That player must then return the ball, up through the top of their own square and down through any other player's square. Each player is only allowed one touch, although we often add a rule permitting a second touch if the ball bounces off the frame.

A player loses if the ball comes down through their square but they fail to return it. That player goes to the end of the line (ie the last seat in the queue), while everyone 'behind' them moves up. For example, if the king loses, they go to the end of the line and everyone else moves up one. However, if the player in square 3 loses, they go to end of the line, while the player in square 4 moves up to 3, the player on seat 5 moves up to square 4, and everyone else in the line of seats moves up.

A valid serve goes up through the king's square, and down into another player's square, without touching the frame. We allow the king a second serve if the first serve is bad for any reason - if the second serve fails, the king loses. Generally speaking, play moves so quickly that even if a player is last in line, they will be back in the game in just a minute or two.

#What To Print#
For four-square, you will need to print:
* 1x centrepiece
* 4x edge
* 4x corner

#Plastic Pipe#
You will also need 40mm plastic waste pipe for the frame - I used FloPlas WPO2 40mm White Polypropylene Waste Pipe. '40mm' pipes are available in different materials and have slightly different diameters - adjust the parameters in the OpenSCAD file if your measurements are different - a good, tight fit is necessary. For four-square you will need to cut:

• 12 horizontals - I cut mine to 1.5 metre lengths, which works well for the game and means I can get two out of each standard 3-metre length of pipe
• 9 verticals - I cut these to 2 metre lengths - high enough that they're 'overhead' for everyone, but not beyond the abilities of primary-school children

#Assembling the Frame#
If you have many helpers, assemble the frame top on the ground, then lift the assembled top frame onto the uprights. This is quick and easy. However, it is also possible for one person to assemble the frame on their own. To do this, start with the centre connector and an edge connector. Assemble these into a n-shape with two uprights and a crosspiece. Now attach a corner connector to a cross piece and an upright. Get the n-shape standing upright and attach the cross piece with the corner - now you have half a 'square', free standing. It should be easy to complete this square, and then build out the rest of the frame from there.

Because the pipes are not very rigid, you may find the frame a little flexible/wobbly. This doesn't seem to interfere with play, and the connector parts are strong enough to handle the stresses. The friction fit joints seem to hold reliably, but after a hard spike or epic collision they may need a quick tightening-up.