[kens]

I've seen a few things on chips that don't make sense, such as wires to nowhere. Then I figured out that these were bug fixes where they had cut connections.

Occasionally I find interesting chip art such as a tiger on a Dallas Semiconductor chip: https://en.wikipedia.org/wiki/Chip_art

[kayson]

Chip art is a lot of fun! Years ago when I was working at a startup, we had a wooden statue in the office of a monkey holding a cell phone. Over time he was further accessorized with a hardhat and an official company badge. On one of our prototype tapeouts, we made a not-insignificant effort to render a proper photo of it onto the top layer metal.

The tricky thing was getting multiple colors (shades, really) using what amounts to a single color. Back then, we didn't have any fancy filters like "sketch mode" to turn it into a line drawing, and we were limited to some extent by process design rules for metal size, spacing, density, etc.

We ended up opening the image in GIMP, and converting it to grayscale, then true black and white (1-bit color) by upscaling and using some filter where it preserves the shades by setting the average density of black pixels in an area to match the shade of gray of the pixel in the original. Then we wrote a script that mapped black pixels to solid metal, and white pixels to empty space, on a grid in such a way that all Design Rules were met.

It wasn't a perfect result but I think it turned out alright! https://imgur.com/a/AkB10A0

[parsecs]

What was the function of that piece of silicon?

[kayson]

The whole die was a cellular transceiver. If I remember correctly that particular spot happened to be empty on the top layer. Foundries require a minimum density of metal on every layer, so we would have had to put dummy pieces of metal there anyways. We figured why not put a picture