Zerdly

Mini Golf

Drag back from the ball and let go. The cup is a speed gate rather than a target, so a putt over 1.64 m/s runs straight across it. 5 rounds, holes proved holeable before you see them, and a daily hole.

Setting up the green…

Aim decides whether you can. Power decides whether you do.

The hole will not take a fast ball. A ball crossing the cup is unsupported for the width it crosses, so it is falling for that time — and it only drops if it has fallen its own radius before the far rim catches it. On a 108 mm hole with a 43 mm ball that comes out at 1.64 m/s dead centre, and only 0.71 m/s if you catch the rim. Nothing was tuned to produce those numbers; they are what the arithmetic gives, and they land on the roughly 1.6 m/s at which a real putt lips out.

We measured what that is worth against aim, because a cup threshold nobody can feel is decoration. Playing 23,040 shots over thirty generated holes, through the same physics you play: at an aim that can hole, 3 of 16 power settings drop it — about 19% of the dial — and at a power that can hole, 1 of 48 aim settings do, a single 7.5° slot.

So the two controls are not two ways of doing the same thing. Point within about seven degrees or nothing will drop however you strike it; then a fifth of the power dial will drop it and four fifths will not. Both are real, which is not what a route like this can assume.

How to play

Drag back from the ball and let go, the way you would pull a cue back. The direction you drag is the direction the ball goes, and how far you pull sets the power. The dotted line shows where the ball will finish if nothing is in the way.

The pads under the green do the same job one step at a time — the aim a degree at a time, the power in notches — with the angle and the roll in metres printed beside them before you commit.

Power is a speed, not a distance. A full putt leaves at 6.0 m/s, which carries 20.5 m on the green, 32.7 m on a fast strip and 9.5 m through rough. Half power is the same stroke everywhere and a different distance everywhere.

The stroke ends when the ball drops or comes to rest — under 30 mm a second. Going out of bounds costs 1 stroke and you drop where you left the green.

Tips

  • Aim first, then ease off. Getting the line right is what makes a putt possible at all; once it is, hitting it softly is what makes it drop.
  • Dying at the hole beats reaching it. A putt that would stop a hand past the cup arrives slowly enough to fall in. One that would stop two metres past it arrives far too fast.
  • A rail is your friend on a dogleg. The ball keeps most of its speed off timber, so a bank shot is often shorter than going the long way round.
  • Rough eats a putt: the same stroke carries about a 46% as far. Cross it at an angle rather than sitting in it.

Privacy and local play

Everything runs in your browser. There is no sign-in, no server and no gameplay API: your best rounds and settings are stored on this device only, under keys belonging to this game alone, and clearing them does not touch anything else on Zerdly.

Questions

Why did my putt run straight over the hole?
Because it was too fast, and that is a real rule rather than bad luck. A ball crossing the cup is unsupported for the width it crosses, so it falls for that time — and it only drops in if it has fallen its own radius before the far rim catches it. On a 108 mm hole with a 43 mm ball that works out at 1.64 m/s dead centre. Nothing was tuned to make that happen; it is what the arithmetic gives, and it happens to match the roughly 1.6 m/s at which a real putt lips out.
So is aim or power the skill?
Both, and they do different jobs — we measured it rather than guessing. Playing 23,040 shots over thirty generated holes through the same physics you play: at an aim that can hole, a median of 3 of 16 power settings drop it (about 19% of the dial). At a power that can hole, a median of 1 of 48 aim settings do — a single 7.5° slot. Aim decides whether you can; power decides whether you do.
What counts as the ball having stopped?
Under 30 mm a second. That is a rule in the rules layer rather than a rounding error in the physics, because "the stroke ends when the ball rests" is a threshold and a threshold decides outcomes — a ball creeping toward the cup has either got there or it has not.
How far does a full-power putt go?
About 20.5 m on the green. The same putt runs 32.7 m on a fast strip and only 9.5 m through rough, because power sets the SPEED the ball leaves at and the surface decides how far that carries. Half power is the same stroke everywhere and a different distance everywhere, which is what a golfer means by hitting it the same.
Are the holes actually possible?
Yes, and it is proved rather than assumed. Every generated hole is played before it is offered: a grid of aims and powers from the tee, then from wherever the best shot finished, and again. A hole is only used if several different lines get in — one holing shot passes 'is it possible' and fails every player.
What happens if I go out of bounds?
You drop where you left the green and add 1 stroke. The card shows the penalty as a number in the cell rather than only a colour, so a round reads the same in greyscale.
Is there a limit to how many strokes a hole can take?
Yes — 20 on any hole, after which you pick up. Two of the rounds add their own rule on top: one caps a hole and scores it as par so a bad hole costs a known amount, and the long round drops your worst holes so one disaster does not decide it.
Are the rounds just three lengths of the same game?
No, and the spec forbids exactly that. 5 rounds: the short one is 7 strokes of par and nothing else; one caps each hole; the long one is 52 of par and drops your worst; one composes only holes you cannot reach in a straight line; and the daily is one hole, the same for everybody, seeded by the UTC date.
What do the different surfaces do?
They change how far the ball carries and nothing else — there are 5 of them. Rough is heavy, a fast strip runs, sand is heavy and water costs you a stroke. There is nothing to collect and nothing to dodge.
Can I play without a mouse?
Yes. The pads under the green turn the aim a degree at a time and move the power in steps, and the readout says the angle and the roll in metres before you commit. A route whose only control was a drag would be unplayable without a pointer.
Is the daily hole the same for everyone?
Yes. It is generated from the UTC date and nothing else, and it goes through the same proof as every other hole — so two people on opposite sides of the world putt at the same hole on the same day.
Does reduced motion make it easier?
No. It calms the aim line and the meter; it changes no rule, no threshold and no result. The route also follows your operating system's reduced-motion setting automatically.
Why is there no leaderboard?
There is no server and no account, so there is nobody to compare you with. Your best rounds and settings live in this browser and nowhere else.

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