Happy Two Pi(e) Day 2025!

It's that time of year again folks! By which I mean Tau Day, 6/28, and Michael Hartl's annual State of the Tau update. Looking back over my blog, I realize this marks ten years since I made my first post on Tau Day back in 2015 (with one every year since except for 2017, where I seem to have simply forgot).

Since you're probably tired of me explaining over and over again why \(\tau=2\pi\) is a more natural circle constant than \(\pi\), let me instead share some (photos of) actual pies. You see, up in the Puʻu Makaʻala Natural Area Reserve where I work a lot of plants are busy producing various fruits over the summer. Two of those happen to be the native Hawaiian raspberries (Rubus hawaiensis), known as ʻākala, and the native Hawaiian blueberries (Vaccinium reticulatum & V. calicynum), known as ʻōhelo (though they're actually red in color).

ʻŌhelo and ʻākala are both edible, though neither are particularly sweet (and ʻākala in particular can be very tart). Last month someone at work suggested the idea of baking them into a pie (where some added sugar could combat the tartness), and this inspired me enough to go out, buy a pie pan, and make some practice pies. I used a recipe for blueberry & raspberry pie (which I'm pretty sure I made while I was in Australia), using store-bought berries to stand in for the Hawaiian versions.

Before baking…

…and after!

And I think it came it pretty well! This is the second of two practice pies I made, since the berries I bought turned out to be just enough for two. The top cover design is meant to be a stylized view of a D20 die (or icosahedron), since we're the 20th domain in NEON and often abbreviated D20 (and have shirts with such a design on them). This was my first time making my own dough (I just used pre-made pie crusts in Australia), and while I think it could be slightly tweaked and improved I'm pretty happy with how it came out (both visually and taste-wise!).

I haven't had much time to collect berries from the field the past two weeks, but this week should provide me opportunity. Yesterday a friend of mine sent me a picture of an ʻākala pie from another conservation team on the island, so I'm clearly not the only person experimenting with it. A hui hou!