I started rock climbing because it freed me from the monotony of training for sprint kayak. Climbing on rock is athletic and inspiring, and takes you to beautiful places. It can also be dangerous. Your decisions matter when you're hanging from tired fingers far off the ground. The danger and the ticking clock of your tired muscles forces you to make each next move quickly and intuitively. Think too hard and you'll start to get tired. Get too tired and you'll fall. These consequences force me to fight my tendency to reduce sport to a plodding checklist.

Sprint kayak, trail running, olympic lifting, building an airplane - many of my favorite hobbies and a good portion of my work as a software developer have this checklist flavor. I've always been this way. Growing up I loved to put together kits of Legos. I'd sit in silence for hours, going through each instruction step by step until I'd finished the kit with every piece in just the right place.

I would almost never experiment and make anything new with those sets; once I'd completed the project I'd shelve it, happy to have completed it according to plan. I wasn't great at video games, but I loved to read walkthroughs and mechanically execute each walkthrough step in the game without trying to figure it out myself.

I've always had some deep embarrassment about how much I like plodding projects; indeed, my biggest fear in my teens was that I would never become "a creative person".

My parents run a brainteaser puzzle company. My dad in particular is a very creative dude. I remember back in high school showing Dad a list of Microsoft software interview questions, famous for their trickiness and brainteaser-ish style. One of the questions was, "how many marbles could you fit into a school bus?" This is meant to be a test of the candidate's ability to sketch out the quantitative dimensions of the problem, assume some volume for the bus, do the calculations quickly to see how many marbles you might stuff inside, minus some marbles to make room for seats, and so on. Dad's answer?

"Well, if the marbles were big enough... I suppose 3?"

Holy shit. Where does an answer like that come from?

I spent a good chunk of my 20s trying to answer this question, and trying to find arenas in my mind where gems like the marble answer would bubble up unannounced from those creative depths, sent as a gift from the boys in the basement.

Rock climbing, of all things, was some of the best practice I found for breaking myself free of the checklist mentality, the goal-driven urge to line my life with checkboxes and tasks.

Why climbing? A climbing route is a test of how willing you are to give in to creative uncertainty. You can apply the lego style to your physical training, but when you decide to start up a new route you have to accept the fact that you don't know what's going to happen. If you want to make it safely up the wall you have to accept that ideas about what to do next are going to arise right when you need them, not before. You have to believe that this is going to happen without being able to study the next page of instructions. If you try to break out of this mode and plan mid-move, you'll realize what you're doing, notice that you're hanging far off the ground with no explicit clue about what to do next and you'll freak out.

If you can learn to relax, you'll watch with astonishment as your body improvises, comes up with the next idea, survives. You'll relax and realize that, just maybe, this particular sort of relaxation is the key to creative play.