Kane Williamson is scrambling.
At his best, this is an imperious batter. Compact, assured, supremely accomplished. Not a player in the vein of a Babar Azam, or even a Rohit Sharma, who both bat as if born into an obscene inheritance of talent. There are gifts for Williamson too; they are quickened by something else.
But, last ball of a Test, the shadow of the Hagley Oval pavilion darkening a surface that still offers bounce and movement for the bowler, who is operating with a ball that is 70 overs old and as such has long since lost its shine, there Williamson is. He has attempted to hook this head-high ball (he might fairly contend it passed higher than his head), and he has missed.
So now, he has to go to Plan B. And everyone knows what Plan B is.
Before he has even left his crease, batting partner Neil Wagner is halfway down the pitch. Wagner is nursing a hamstring tear and a bulging disc in his spine. But this is Wagner, who is a cricketer powered so completely by willpower that the physical details of what his body can realistically achieve fade into insignificance. Wagner desperately wants to be halfway down the pitch at this moment. So, it ends up not mattering what the nerves near his spine, or his hamstring, are telling him. ("Dear God, what is your problem?" "We've had enough." "Please stop, you f****ng madman." - Some of the things his body would be saying, if we had to hazard a guess.)
Williamson is still on the crease while Wagner is halfway down, because the bowler Asitha Fernando is playing the situation almost perfectly. He has bowled a bouncer, which Williamson has to put his weight on his back foot to play. Because he is going back, it means he has to reverse his momentum to attempt the single that New Zealand require to win the game. In such situations, run outs are frequently the most likely dismissal - the bowler beating the bat, the keeper with one glove off throwing down the stumps closest to them, the non-striking batter caught short.
But Asitha is ready for his plan B too. Niroshan Dickwella, the wicketkeeper, misses the stumps closest to him, which means that Wagner makes his ground comfortably. But Asitha knows that if Dickwella is aiming at those stumps, he can collect on his follow through and throw down the next set. His thinking is spectacular. It is almost perfect.
Earlier in the over, Asitha collected a bounce throw from the deep and effected a run out with minimum fuss and total efficiency. If there is any player on the field matching Williamson's nous and Wagner's effort right now, it is Asitha. His first 11 overs in this innings cost 14 runs. In the previous three overs before this one, when New Zealand have been trying to smash it, he conceded just 15. He's keeping Sri Lanka in the match.
On this last ball, Asitha gets into perfect position to collect the ball as Williamson is scrambling, he swivels on his left heel, and almost in the same movement, he throws down the stumps at the non-striker's end.
It is an almost perfect play. He's beaten the batter and pushed him on to the back foot. He's collected the throw and hit the stumps direct. But Asitha sends the throw in on the bounce. It hits the pitch halfway between him and middle stump. The bails fly off. Some close fielders are excited.
But here is the physics: The bounce helped the ball find its target, but it slowed the throw down. Not only did the ball have a greater distance to travel, it had to be deflected off the ground, which always absorbs some energy. Williamson made his ground by a fraction of a second. This, very likely, was the difference between a draw for New Zealand, and a victory.
On his 93rd Test, the act that will define this game, is Williamson's sprinting and diving. So that only a perfect play, and not an almost perfect play, could catch him short.
This is New Zealands greatest men's batter. The late Martin Crowe - the only player whose record could seriously have stood up to Williamson's - happily acknowledged this many years ago. In the last Test Williamson played, he became the most prolific Test batter from his country and put the matter to rest. This 121 not out was his second second-innings hundred in succession.
Others have perhaps forged more eye-catching careers through their explosive batting, or their charisma, or the effect they have had on foreign leagues and foreign teams.
Williamson once described the feeling of batting alongside the bonkers Brendon McCullum as being "like the library in a theme park".
Theme parks, a modern phenomenon, are the venue of glorious, but transitory, entertainment. They are lit up all over, joyful squeals lasting late into the night, kids flitting from ride to ride, the bang-badoosh-whoosh of rollercoasters the scene of screaming and indescribable fun for years, but eventually turning into rusting monuments to human elation decades later, the place decommissioned, the park having made its money, and moved on.
Libraries, meanwhile, have been around for millennia. Quietly enriching the human experience, shaping history in all sorts of subtle ways, forging progress, informing cerebral pleasures. They will be around for millennia yet.
Today, Williamson, the greatest batter New Zealand has ever produced in its long cricketing history had to scramble a bye, to win a Test off the last delivery. And he scrambled the hell out of it.