The illusion is very similar in principle and performance to the older "Thin Model" versions of sawing a woman in half, with the exception that the boxes used to cover the assistant being divided are clear, rather than opaque. In basic concept, it is very similar to the transparent sawing developed by Les Arnold in the late 1970s. However, in the Pendragons version, the boxes are much smaller, and are never covered at any point during the illusion. As a result, the assistant within the boxes remains in full view throughout, making this a particularly baffling illusion for the audience.
The illusion usually begins with the magician showing the audience a low table, designed to split into two halves. The main assistant is then introduced, and lies down on the table. Other assistants then place two boxes over the assistant, with clear sides and tops. As the upper box is placed over them, the main assistant extends their arm out of the open side of the box, while their head and feet extend out of the ends of the two boxes. Small stocks are then used to restrain the assistant's feet and neck. Because the boxes have clear sides, the audience is able to see right through them, and can see that the assistant has not curled up inside the upper box, as is described in many commonly available magic books for the "Thin Model" sawing. The magician then cuts through the box using either a saw or sword (although some performers skip this step), and dividers are placed into the box either side of the cut. With the dividers in place, the two halves of the table are unlocked and pulled apart. As the assistant has been in full view of the audience throughout the illusion, it appears that they have been separated into two halves, the impossibility of this situation helping to give the illusion its name. The halves of the table are then pushed back together, the dividers removed, and the unharmed assistant released from the stocks and boxes.
While she was in a relationship with David Copperfield and not otherwise occupied with modelling work, Claudia Schiffer often assisted Copperfield in his stage shows as a "special guest assistant". Part of these shows was a performance of Clearly Impossible, with Schiffer as the assistant being sawed in half by Copperfield.
While appearing on a local TV talk show during a promotional visit to Japan in 2006, actress Mischa Barton took part in a performance of the illusion in which she was sawed in half by a local magician.
While presenting SM:TV Live, British TV presenter Cat Deeley was the first British celebrity to be sawed in half in a version of Clearly Impossible.
During a promotional visit to Europe, Jessica Simpson participated in a performance of the illusion where she was sawed in half by illusionist Hans Klok, who used a large circular saw to divide her in two.
When she appeared on a Mexican talk show, Penélope Cruz took part in a performance of this illusion.
In February and March 2012, Klok visited the UK with his stage show The Houdini Experience, playing a five-week run. During the press night at the Peacock Theatre in London, he amazed the audience of celebrity guests when he invited actress Louisa Lytton up onto the stage and, without any prior rehearsal, sawed her in half in his Clearly Impossible illusion.
The assistant's trousers have a rigid frame that locks into place so she can walk normally, but when she is lying down she can pull her legs back and under him or her. Some performances hint at this and show it when The Twins perform it. If one looks carefully, false feet can be seen being pushed up or down.
- "The Art of Magic". Magic Television. Retrieved February 22, 2012.
- Schneider, A., "A New Clear Sawing", Genii magazine, June 1993 (Vol 56, No 6).
- Moehring, J., "The Century: The Pendragons", Magic magazine, Vol.8 No.12 (August 1999).
- The Pendragons performing Clearly Impossible in Cincinnati 1998 PBS TV Special 
- Bryant, S. "Claudia Schiffer: From Supermodel to Magician's Assistant". Genii magazine, August 1996, (Vol 59, No 8.).
- David Copperfield AskMen.com. Retrieved 26 April 2009.
- Top 10 Celebrity Odd Couples Film.com. Retrieved 26 April 2009
- YouTube clip of performance