Folded/Convoluted High HX Area Stamped Surface

Is there any common everyday thin metal waffle stamped item that has a surface area about an order of magnitude more than the spanned area?
It could be any metal at least as rigid as aluminum.
At first it looked like an easy search but now it looks like the only way to get it is to machine a die.
Bret Cahill
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wrote:

Not waffle: but aluminum gills on refrigeration pipe have immense surface area for a modest plan view size.
Brian Whatcott Altus OK
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Is that the ribbon or confetti fin material on ac or heat pump evaporators and condensers?
A convoluted area would be better than fins as the temp. drops off toward the tip of a fin.
Ideally it should look like those electron density charts in quantum mechanics, tall peaks and deep valleys.
Bret Cahill
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