Juggling is good for both reflex and cortex, according to a study conducted by a team at the University of Oxford in 2009. While honing the circus skill has some pretty obvious benefits—improved peripheral vision and general coordination to name two—the researchers also claimed it grows your brain.

Twenty-four subjects, none of whom could juggle, were split into two groups. Over six weeks, one group took a crash course in juggling, with weekly lessons to supplement their own daily half-hour practice sessions. The other group, acting as the control, learnt zilch, as oblivious of juggling as when they first volunteered.

To open and close the research, each participant was given an fMRI scan: the clinical equivalent of before and after photos. The images allowed Dr Heidi Johansen-Berg, the study’s lead, to gauge whether any brain-changes had occurred during the interim.

Among the trainee jugglers, the news was encouraging. As Johansen-Berg summarised, ‘[Our study suggests] that in healthy adults, learning a new skill over a relatively short period of six weeks is changing the brain; it’s changing the size of brain areas involved in the task, and it’s changing the wiring between different brain areas.’

To be specific, each juggler’s brain displayed increased density in the myelin sheath, the pale cellular matter that insulates our axons, while the juggling muggle—the non-learner—displayed the same brain as before.

The media cheered. Juggling is beneficial, read every spin-off article. Though Johansen-Berg was quick to temper the hype: ‘This doesn’t mean that everyone should go out and start juggling to improve their brains. We chose juggling purely as a complex new skill for people to learn.’

Replace juggling for crossword solving, and the repercussions follow. While jumbling letters and double-meaning won’t improve your chances of catching your Vegemite toast before it hits the lino, the new-found skill is bound to boost your mental agility, your semantic memory, your problem-solving and every other dimension that Part One has touched on.

Like the juggling study, the data surrounding the act of solving isn’t foolproof but it is optimistic, every sign suggesting the custom is nourishing the mind. And unlike juggling, ten times the research has been held in puzzle-play, with each paper confirming that the solver’s brain is a boosted brain, as nimble as an acrobat.

The only thing lacking now is a circus ring where you can put your skills to the test. For all the promises of Part One, the real show hasn’t started. To be a lion tamer, you need to find a chair and tame a lion. That’s where Part Two does the trick, where talk of brain health plays second fiddle to hands-on letter juggling.

I’ve already tossed a few curveballs your way, a few sidebar puzzles by way of rehearsal, giving your brain a sense of solving solo in the spotlight. So far, in earlier chapters, I’ve served up pun-clues and alphagrams, memory games and celebrity cocktails: how many answers did you catch?

Not that it matters—you’re a juggler in training. Clumsiness is natural. Besides, if this book was a circus manual, then you’d need some props. Rubber chickens to lob. Skittles and balls. Everything till now has been a barker’s cry, a drum-roll to lure you into the tent, making the call for practice overdue.

I could be dogmatic, of course. I could say:

Step one: Bundle two socks into a ball.

Step two: Hold the ball in one hand, standing over a bed or table, and toss the bundle upwards.

Step three: Catch the ball in your hand.

Step four: Repeat.

And so on. Throw, catch, throw, repeat. As soon as the neurons have started firing in sync, we could graduate to lobbing two bundles. Next step: chainsaws.

But this language would be wasted without the props on hand. After Part One, we all know puzzling is good for the brain, so what say we puzzle? Let’s roll up, roll up, and enter Part Two, all the better to furnish your big top.

Johansen-Berg, the juggling researcher, concluded her findings with a familiar tune: ‘There is a “use it or lose it” school of thought, in which any way of keeping the brain working is a good thing, such as going for a walk or doing a crossword.’

That’s our cue, folks. It’s showtime.