Take 25/30 pallets,a box of 4in nails,an hammer,and one of these can be made as solid as anything professional out there,done right.When made relying on gravity and the weight of the pallets for strength,you can end up with pallets coming down directly onto ya after a run.Very dangerous.It's just as easy to do it right as it is to do it wrong.A box of nails and an hammer.=Wicked quarter.=Headache for council.Ha-ha. Gringo.