Seven a side, three of them stacked right

Seven players, and only one of them snaps it

There is a centre on the ball, a quarterback four yards behind him, and a running back five yards to the quarterback's right. The other four are eligible receivers, and three of them are right: an outside man near the sideline, then two more a yard off the line, laddered six yards apart, the innermost of them sitting exactly on the right hash. The fourth receiver is alone on the left.

There is no offensive line to speak of. Seven a side means the centre releases after the snap and the quarterback has whatever the rush rules give him, which changes what a formation is for entirely. In eleven-a-side football an alignment creates blocking angles. Here it only creates coverage problems.

Read the gaps, not the sidelines

The pitch under this drawing is a full gridiron, fifty-three yards from sideline to sideline. A flag field is usually twenty-five or thirty. So the numbers to copy off the picture are the gaps between players, not the distances to the paint: six yards between each of the trips is the spacing that travels to any field, and the outside receiver's split shrinks to whatever your sideline gives him.

Six yards is the useful number because it is far enough that one defender cannot cover two of them and close enough that all three are inside the same throw. Draw them three yards apart and the routes run into each other. Draw them ten apart and it stops being trips and becomes three isolated receivers.

Building plays from it

• Three defenders, three receivers, one rule. Most seven-a-side defences play man. Draw the three routes at three different depths — flat, five yards, deep — and the coverage has to run through itself.
• Use the back. He and the split end are the only players on the left half of the field. Send him out of the backfield to the empty side and count who is left to take him.
• Then take the trips away. Redraw the same seven with two receivers a side and see how much easier the defence's job became. That comparison sells the formation to a squad better than any explanation.

Open it in the designer, set the width of the field you actually play on, then draw the three routes you can get thrown inside four seconds.