I Went Looking for the Doubling Cube

Dear the version of me from three hours ago — the one still rummaging in the games drawer for the backgammon doubling cube, hand about to close on a tin of double-six dominoes nobody in this house has ever actually played:

Put the cube down. You are not going to play backgammon tonight.

I need to warn you about the sound, because the sound is the trap. You’ll stand five tiles on end just to see, and tip the leader with one finger, and the collapse will travel away from you as a small ascending click-click-click-click — and something old and greedy at the base of your skull will say again. You will obey. One row becomes a curve. The curve wants a branch. When you next look up it will be well past midnight, there will be a tin’s worth of dominoes fanned across the kitchen table in a shape you never decided on, and you will have watched competitive builders topple gradient fields of ten thousand tiles on your phone with the specific hunger of a man who has found a new hole to fall into.

Here is the number I wish you’d had at tile six. The gap. Space them roughly one tile-height apart — the standing height, not the length. Closer than that and they clump, each one falling onto the back of its neighbour before it can gather any speed, and the wave dies mid-table in a sad little heap. Wider and the faller lands flat on the felt without reaching the next tile at all — the builders call that a skip, and everything downstream just sits there afterward, upright and smug, while the run stops dead ten centimetres short. You’ll find the spacing by feel eventually. You’ll also waste half an hour first, and I’d rather spare you that.

A thing that will quietly delight you, because it flatters the part of you that likes a governed system: the cascade does not care how grand your build is. The topple front travels at about a metre per second, more or less, whether it’s ten tiles or ten thousand. You cannot make it hurry by wanting it more. There is no throttle. You do all your work in advance, in silence, on your knees, and then you surrender the whole thing to a fixed and unbribable speed.

Which brings me to the part I didn’t expect to find cruel after a single evening. The payoff destroys the work. Every tile you place exists in order to be gone in four seconds, and — this is the sting — the longer you build, the more you stand to lose in that same four seconds. It inverts everything you learned feeding energy into the Foucault pendulum a few nights ago, where the whole discipline was delivering a nudge at the exact instant of least disturbance so you didn’t corrupt the swing. Here the discipline is the opposite: deliver no energy, none, not a breath, until the very end. The escapement problem run backward. You spend the night learning not to touch.

So learn the one technique that separates a finished run from heartbreak, and learn it early. Build in safety gaps — leave a deliberate missing tile between finished sections, or set a little barrier behind the tile you’re placing, so that if your sleeve catches (and it will; you’ll lose about forty tiles tonight to a cuff you forgot you were wearing) the damage stops at the gap instead of unzipping the whole table. You fill the gaps in last, all at once, just before you trigger. Take comfort that this failure scales all the way up: the year they built four million tiles for Domino Day, a sparrow flew into the hall and knocked over twenty-three thousand of them, four days early. Your cuff is nothing.

I’ll be honest, because a letter to yourself is no place to posture. I don’t yet know if I have the patience for the ten-thousand-tile field. Tonight’s entire run was maybe two hundred tiles, and I lost half of it twice before it ran clean. But someone has built a working binary adder out of these — merge two lines for an OR, block one for an AND — a mechanical logic circuit that computes as it falls, and I have not stopped thinking about it since I read it.

You were only looking for the doubling cube. Sorry.

— me, three hours older, still hearing the click