They're either usually formed in a mold by pressing. The resulting "green" tile is sometimes stamped or patterned, and glaze is applied. Then they are fired in a kiln.

You need pretty strict tolerances on the dimensions of this Spectre tile, I think. Normal Penrose tiles might be easier.

That said I have no idea in the first place how you'd get your hands on bespoke tiles...

The grout when tiling allows for a fair amount of fudging things, though from experience exactly dimensioned tiles are MUCH easier to work with.

With periodic tilings you can uniformly scale them to make room for grout of any thickness. Intuitively, it seems like aperiodic tiles would have to be manufactured slightly too small to leave room for grout, and the tiling would only work if the grout was exactly the right thickness. I wouldn't want to lay them.

Oh that's an interesting point actually. I hadn't considered the tiles needing to be designed around the grout width. Still, I don't think you'd need to be particularly exact with the tiles or grout. In fact it would probably be best to eyeball it and make sure you work outward from a single spot. Trying to tile by e.g. starting around the outside edges and working inwards is bound to get you in trouble with compounding error.

This is sounding like a more interesting project by the minute.

On reflection I've realised my point was nonsense. Sorry.

It's not nonsense. The fact that aperiodic tiles like these need to be designed for a specific grout width is non-obvious and quite interesting.

Here's how encaustic cement tiles are made - with liquid cement, cement powder, a mould, and a press: https://youtu.be/XSp5Tj4yYNc

I recently bought this book : "Arts & Crafts of the Islamic Lands: Principles • Materials • Practice" (Thames and Hudson Ltd, edited by Khaled Azzam).

It has a section on making similar (ish) geometric tiles, although the description is really for square tiles with the geometric design on the face.

From recent experience of drawing and reproducing tiles (including trying to draw the 'hat' monotile) I think the tolerances on your physical tiles would have to be quite small. Either that or make them as a more regular shape and cut out the correct tile from that larger one.

I’ve spent a decent amount of time figuring out to make porcelain tile. The most reliable way to do so and avoid cracking is to use a plaster mold and push slabs of clay into it. Cookie cutter and other slab methods produce too much cracking without heavy duty equipment or maybe a different clay formulation (I’m using standard porcelain which isn’t the easiest material)

any results? What if I made delrin molds?

Plaster is better for ceramics because it helps to evenly dry the clay. Can use delrin to make a plaster mold though!