He's taken his 400th wicket now, and he's done it in fewer Tests than anyone other than Muttiah Muralitharan. It's amply clear that R Ashwin belongs among the very best spin bowlers the game has seen, so there's little need for anyone to build an elaborate case for his greatness. We know already.

So let's talk, instead, about the beauty of his bowling.

Let's talk about wickets No. 396 and 399. Ollie Pope is the batsman on both occasions, and both times he's bowled after being beaten on the outside edge. Ashwin does this from around the wicket on day one of the Ahmedabad Test, and from over the wicket on day two.

Put the two balls side-by-side, and it's mesmerising.

There's a lot to look at, but keep your eyes on Pope for the moment. From his low backlift and his crouched forward press, it's clear he has the skiddiness of the pink ball on this Motera pitch, and the threat of lbw, in the back of his mind.

Then Ashwin delivers, and Pope's front foot begins to dance. First it strides forward and outwards, and then it changes direction abruptly, sliding backwards towards leg stump. This happens on February 24, and again on February 25.

It's unclear if Pope himself can explain why he does this, twice, but this is what Ashwin's flight can do to batsmen. They think they know where the ball will land, until it changes direction in midair, upsetting all their calculations.

This puppetry of drift and dip leaves Pope in a severely compromised position. His weight isn't going towards the ball, and the diagonal drag-back of his front foot opens his body up, causing his bat to slice across the line of the ball in order to block it. And he isn't close enough to the pitch of the ball to be able to cover for any vagaries in turn.

From where he is, Pope can only guess as to which way the ball will go. He plays for turn both times, and it may even be the wise thing to do - assuming there's any conscious thought involved - because he's likelier to be bowled or lbw if he's beaten on the inside edge.

But the ball goes on straight, beats the outside edge, beats Pope's back leg - which slides across to the off side, partly to restore his balance and partly in a desperate attempt to keep him from getting bowled - and hits off stump anyway.

This happens on February 24, from around the wicket, and again on February 25, from over. Even Rishabh Pant's hands and feet are caught up in this uncanny choreography.

It's an echo of all the other times that Ashwin has gotten the same batsman out in similar fashion on multiple occasions: Kumar Sangakkkara - four times in four innings in his last Test series, three times caught at slip; Kane Williamson - four times in four innings during New Zealand's 2016 tour of India, bowled or lbw each time; Alastair Cook - bowled in each innings of the 2018 Edgbaston Test, pitching leg and hitting off both times.

It's an illustration of Ashwin's ability to spot holes in batting technique and his skill in delivering the perfect ball to exploit them. But equally, it's an illustration of his mastery of spin bowling's first principles: the ability to give the ball an almighty rip, land it exactly where he wants it to, and to do both those things again and again while cycling through all his variations of pace and trajectory and grip and release.

Sometimes there's a grand plan when you get two balls that look so alike. Sometimes there isn't. Either way, it's something to savour, and to talk about for years.