If, like me, you missed

Tau Day a few months back, you can still celebrate everyone's favourite underdog numerical constant. So let's make a "

?-shirt" to counter those all those lame Pi shirts.

Here's how to make a Tau shirt in Mathematica.

Start by getting some digits of tau:

digits = Characters @ ToString[N[2*Pi, 10000]];

Now let's draw a really big Tau, and turn it into an array of pixels:

tau = Style["?", FontSize -> 128, FontFamily -> "Times"];

tau = Binarize @ Rasterize @ tau;

Next, all we have to do is walk through the pixels in raster order, creating the next glyph at the location of each successive black pixel:

i = 1;

glyphs = MapIndexed[

If[#1 == 0, Text[ digits[[i++]], {1,-1.3} * Reverse[#2] ]&,

ImageData[tau], {2}

];

And render with a cool font:

Graphics[Style[glyphs, FontFamily -> "Ubuntu"], ImageSize -> 420]

Now to PDF for printing (and thence to https://www.shirts.io/).

Export["?.pdf", %]

Unfortunately the font isn't preserved, but the fight for tau equality was never going to be easy.