Here is a novel, useful way to rig a 4m * 4m tarp to stand up to strong winds and rain. This rig will keep about eight people out of the rain.

The side guy-line is about 10 metres long and is threaded through the grommets on the tarp and staked down with three stakes. It is passed around the centre stake as shown below and finished with rolling hitches on the ends.

The stick keeps the ridge taut without stressing the grommet; in a strong wind the stick would break before the grommet blew out.

The ridge line extends from all the way under the ridge, it is made fast to the poles with clove hitches  and leads through the centre grommet on the ridge, is looped around a stick, lead back through the grommet and then lead to the other end of the ridge where the process is repeated.