As someone who frequently wears high heels, I have to say the prospect of little screws on my dinner shoes is less than attractive. However, a heel like this on everyday walking shoes (i.e. winter boots which tend to have thicker, chunkier heels which could more successfully hide the screws), is a possibility. Not too sure about the stability of such a heel, but engineers out there can probably figure something out.

Actually, the more I think about it, it's a great idea. It would save many women the hassle of having to carry their heels while wearing thick socks and sneakers on their commutes.

High heel shoe fetishists will really "get a kick" out of this (pun intended)

I don't have really pointy heel shoes, but i have boots with really big heels. And when i wear them to school dances after an hour my feet really hurt, so thats a great idea.

Also really handy for driving! I cannot drive in high heels as the heel gets stuck under the pedal (Arrggh!) so have to take one shoe off all the time.

Actually, I don’t really wear high heels, but of course, as the occasion calls for it, high heels are desired to complement our whole attire. this idea would really favor most people who are not used to wearing high heeled shoes- this suggestion will provide safety and ease to women. very helpful and great idea!

How about fold-and-lock heels? The heels can be locked in the up position for height, or fold into the shoe for more comfortable walking.

Also, are there negative heels (i.e. shoes that make you shorter, not taller)? I am over 6' and hate walking into tree limbs, light fixtures, etc.

The problem comes in where you lower the heel and the angled portion of the shoe near the ball of the foot would continue to push the toes up. So the person would be very uncomfortable. In addition to screwing the heal up to make it shorter, the portion of the sole near the ball of the foot would need to be straightened out. The sole torsionally needs to be rigid for stability. So two piano hinges side by side might work to allow a radius for the ball of the foot. The forepart of the toe box would be strapped to the toes to keep from dragging on the floor. Another alternative for the heels is to allow them to snap on and off. A number of durable latching mechanisms exists that can withstand many tons of loading and high g's in shock.