The best next tap: inside Carillon's hint

What Carillon's hint lights up, how the solver picks one dot from the field as it stands, what a hint costs, and how to use it to learn a field rather than skip it.

Shravan GoswamiShravan GoswamiMakes the gamesShravan runs Chaosmos. He designs the games, plays every build on his phone, and decides what ships., updated , 5 min read
A late Carillon field dimmed by the hint except for a round window on one big coral dot, its reach circle lit and every dot its ring will pop outlined in white

Carillon’s hint does one small thing. It lights a single dot, the best tap you can make from where the field is right now, and then it gets out of the way. It never plays the level for you, and it never shows more than one step. I wanted it that way so that a hint teaches you something about the field instead of ending the puzzle.

Asking for one

Tap the light bulb at the top right of the play screen, or press H on a keyboard.

If a chain is still spreading when you ask, the hint waits for it to finish, so it always plans from a field that has settled. Asking never costs a tap or a star.

What lights up

Four things happen together.

  • The screen dims, except for a round window around one dot and its reach.
  • That dot’s reach sweeps out, exactly as if you were holding it.
  • The dots its ring will touch get an outline, so you can see where the chain goes first.
  • The dot starts to pulse, so you can find it again.

One Carillon field twice: as it starts, and with the hint dimming everything except one lavender dot's reach, with two dots outlined inside it

Your first touch lifts the dim and gives you the whole field back. The pulse stays on the dot until you start a chain, so you can hold other dots, check the hint’s reasoning, and tap it when you are ready. Asking again while that dot is still pulsing costs nothing.

How it chooses

Behind the hint is the same solver that set the level’s goal. From the field as it is now, it asks one question of every dot you could tap: if I tap this, can what is left still be cleared in the fewest taps possible from here? The dots that pass are the winning taps.

Often there are several. The hint picks the winning tap that rings off the most dots, the one that clears the most of the field in one go. It never offers a tap that only clears the field by spending the spare while a better one is still there.

In the first four chapters, the winning taps are exactly the starts of chains, the dots no other ring can reach. Many of the rules from chapter 5 on make the order of taps matter as well, and the solver searches for that too. It keeps track of which dots are still there, which heavy bells a ring has already cracked, and how many taps you have made, and it tries the taps from there.

Either way it works on bitmasks, one bit per dot, so following a chain costs a few dozen quick operations instead of a replay of every ring. Only a chord bell, which needs two rings to arrive together, makes it time the rings in full. A fresh level’s first hint is stored with the level, and any later one is worked out in the background, so the screen never freezes while it thinks.

It plans from your field, not from the answer

The hint never replays a stored solution. It reads the field you have, so it still helps after a tap that went nowhere.

In the first four chapters, that is always enough. A tap that misses every start pops some dots but never removes a start, so after one wasted tap every start is still on the field and you still have the taps to reach them all. The hint simply points at the next one.

One Carillon field twice: after a tap that popped little, and then with the hint lighting a big lavender dot and the eight dots its ring touches

Rules change that. A tap in the wrong place can pop an hour bell before it gets the chance to ring by itself, or ring the home note too soon so that it comes back, and then the spare may not be enough. When no clear is left in the taps you have, the hint says so in a short note, “No clear from here. Restart and read it again”, and asking it costs nothing.

All of this is checked on every level. Following the hint alone from the start must clear the field in exactly the goal. Then they waste a tap on purpose and follow it again: it must clear in the fewest taps left, or say honestly that there is no clear. On the first four chapters it must still finish within the spare.

What a hint costs

Every hint on the first 15 levels is free, as many as you like, while you learn how chains spread. After that you get three free hints a day, and the count comes back at midnight by your phone’s clock. A small badge on the bulb shows how many are left, and a play mark appears when the next hint needs a video.

Once the free ones are used, the hint asks “Watch a short video for a hint?”. Not now closes the question, and if no video can play, say because you are offline, you get the hint anyway. The Supporter pack makes every hint free.

Using it without spoiling the level

The hint is a teacher if you let it be. Here is how I use it when I am stuck.

Ask why. When the hint lights a dot, hold that dot’s neighbours. On the first four chapters, none of their outlines will include it, because nothing reaches it. That is the pattern to look for on the next field.

Ask once, then stop. On a level with several chains, take one hint, tap it, and look for the next start yourself.

Ask after a miss. If a tap went wrong, the hint shows what you could have tapped instead, while there is still time to earn two stars.

Look for the rule. In the later chapters, if the hint passes over a big, obvious chain, there is usually a reason. Maybe the home note sits in it and has to wait for your last tap, or a round bell in it has not had its turn yet. Finding that reason is most of the level.

For the habits that make the hint less necessary, read reading a field. For why “nothing reaches it” is exactly the right test, chain reactions as graphs has the maths.

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