40x74 Rectangle with Octominoes

After the success of the new set of hexominoes I got made a while back, I decided to take the obvious next step and get a full set of octominoes cut too. They arrived about a week or so ago; three batches based on David Bird's three 29x34 rectangles construction*. Fluorescent green, fluorescent yellow, and a colour which is supposed to be fluorescent blue but doesn't really glow at all unless you turn a UV torch on it. Then it goes nuts. Again, all came with that sticky protective film on both sides of the acrylic so I spent the first few days just peeling it all off, a few pieces at a time. Fun times.

Fig. 1: The blue pieces look even worse here since the mat underneath them is dark green.

Once free of their protective sticky plastic stuff, I thought I'd break 'em in with a construction, choosing 40x74 simply because it was about the only thing that would fit nicely on the table. I like having the cutting mats there to make sure everything's all lined up and nice, and anything longer or wider than 40x74 wouldn't have fit on them properly.

Solving with physical pieces is a whole 'nother ball game to just solving the way I used to (or used to attempt to, I only ever got one complete solution that way.) For most of the solving process the hardest part by far is just finding the individual pieces you're after. Especially near the start when there are like 300 or more almost identical pieces to sift through.

Once I got to the last 10% of the construction the benefits of physical pieces really started to shine. The repeated backtracking that is just infeasible with drawing the pieces is now a lot more manageable. Which is just as well, because I must have spent close to two hours trying to get the last twenty or so pieces in. There were several times where I had 368 pieces down but the remaining hole was one cell out from the shape of the piece in my hand. That's the worst bit, those near-misses, but at least I suppose they mean I'm on the right track. If there was something terrifying like parity issues going on it would have at least alerted me.

Fig. 2: Getting there...

The entire solution took maybe about 4 or 5 hours total, a little last night and the rest this morning, which is a lot less than it usually took the old way. The little hole of unfinished pieces seemed to drift around as well during the endgame as I solved, eventually ending up right in the bottom-left corner of the photo above when all the pieces finally fell into place.

Fig. 3: Another side-effect of the colour scheme is that it photographs really badly. Especially when it's me holding the camera.

Here's the solution drawn out properly so you can actually make sense of it and tell where one piece ends and another begins:

Fig. 4: The finished rectangle.

Yeah, the spacing between the holes is imperfect. The gaps are 11-12-11 but it's about as good as you can get with an even-by-even rectangle.

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* Side note: Is there any information anywhere about how he constructed this (and his other solutions)? I always assumed he did them with a set of pieces but it's just as likely he did them using just pen and paper. Especially the nonomino patterns, making and using the full set of 1296 pieces would be a tad unwieldy.