Each of its 4 feet have 5 toes.

Each TOE has fine hairs 1/10 of a mm long, packed at 5,000 hairs per sq mm (3,000,000 per sq inch).

EACH HAIR has 400 to 1,000 branches that end in a spatula-like structure about 1/50,000 inch long.

Each foot pad can produce 10 Newtons of adhesive force.
However, each hair has an attractive force 10x stronger than expected.

Modern technology cannot even come close to designing such an incredible structure.
Humans cannot create a material that can be split so finely & packed so tightly.

Each hair is strong enough to support an ant's weight.
One million hairs can support a small child.
The attractive force increases when the hairs are gently pressed into the walking surface.
So the gecko has plenty of attractive force to spare.

The gecko uses surprising little effort when it walks. How? Via unusually complex motions of:
- uncurling its toes to stick
- unpeeling its toes while detaching. The hairs release their grip at an angle of about 30 degrees.

And, how about this amazing fact? The gecko's feet are self-cleaning!!!
Scientists don't know how they keep such fine hairs, clog-free.
(Perhaps the gecko vibrates each hair, 10x the speed of light, to knock of any dirt particles. :-)

Here's the (rewritten) answer, according to Jonathan Sarfati.