The last few weeks of the twins’ lives have been full of momentous change. As they passed the 18-month milestone, loads of new skills have bubbled to the surface. They can sort of handle spoons, they pretty consistently say goodbye with tiny waves, and they’re trying to put on their own clothing. Suddenly they’re little people, rather than babies and it’s exciting to see their personalities emerge.

Of course, along with the more adorable skill sets, have come some more treacherous ones. A desire to climb. The ability to lift toilet seats. A curiosity about every container and what might be inside it. They haven’t quite managed to help one another out of their cribs yet, but that feels imminent. They can reach the kitchen countertops, just enough to grab anything close to the edge.

But lately it’s their running that is the most terrifying to observe. The twins love to run. Their little feet and chubby little legs clomp up and down, arms waving in all directions, as they gather speed. They think it’s as funny to do, as we think it is to watch.

Both twins run with joyful abandon. Meanwhile, our home is full of lovely ceramic tile and hardwood floors. The combination of four little dinner-roll feet, four slippery ankle socks with partly worn-off sticky pads, and the smooth tile and hardwood makes for a real nail-biter. I try to keep them in their shoes as much as possible to avoid major wipe-outs, and though the shoes prevent the slip-and-slide, they don’t prevent slapstick accidents.

A popular game at the moment is a sort of rapid peek-a-boo, where a little goofball runs around a corner in our house at full speed, only to stop briefly before turning around, and coming right back around that same corner, all the while squealing with laughter. This in itself would be fine, save for the occasional misjudgement and bonking sound as a little noggin hits the wall. But it’s never that simple with twins.

See, the twins love to play this game together. And as the game goes on, it’s much like watching a wagon with loose wheels careening down a hill. It’s all fine…until it’s not fine.

Eventually it happens: one twin slams full force into the other. Four arms fly in all directions, four legs tangle up like a car wreck. Two heads bang up against each other with an audible bonk, and they fall to the floor. A moment of silence passes before the torrential rain of tears pours.

This age is most terrifying because in spite of these epic disasters, it feels like just moments pass before they’re at it again, slowly building up to another collision. The memory of the accident is fleeting, and they’re off to the races, laughing and narrowly avoiding each other once again. With twice the laughter and twice the excitement comes twice the danger, and twice the kissing it better.