Anyone that has seen this will surely have figured it out almost immediately - all that is required is a little lateral thinking. Here's my explanation anyway !

Approaching a passer-by David says"Excuse me can I show you something ?" "It's strange", "Look" "I can't understand it", at this point he squats down and places two hands flat on the ground with the fingers pointing directly towards each other.

"Look " "Hmmm ?" "No, Come around here". Asking the 'helper' to come around to the left side of his body.

Still seeming unsure he says "OK, do this with me" lifting his left hand clear of the ground, leaving just his right hand in contact with the ground. "Put your hand on the ground like mine." indicating the position of his right hand which is pointing directly to the left.

"Now do this" - David starts turning his hand anti-clockwise. After a few moments the 'helper' finds that he cannot move his hand any further.

But David continues to turn his hand around - around - and around, until it has passed through an impossible 360 degrees!

David stands up, rubs and massages his shoulder - the helper is speechless.

The 'Secret'.

As David asks his helper the come to the other side he lifts his right hand up slightly and turns it clockwise through 360 degrees and replaces it on the ground in that position. All that is required now, is for David to 'unwind' his arm. Adding suitable sound effects.

This effect is best done wearing a baggy sleeved garment.

As I perform this trick I keep my left hand around my back and at a suitable moment, click my fingers loudly and make a jerking movement with my right shoulder and uttering a low "Aaarrrgh

! " It's a 'killer' !! Try to keep a straight face !