Play
Aim, pick your speed and your rev rate, and watch what the oil does to the ball. Ten frames, scored properly. It runs in the browser — nothing to install.
Faster skids further before it turns.
More revs, more hook once it finds the dry.
Tap the lane to aim. The grey line is your last ball.
The faded grey line after each shot is where your last ball went. That is the useful part: aim, throw, see the gap between the two, adjust.
The lane is oiled for roughly the first 36 feet, and dry after that. On the oil the ball skids and holds its line. Once it reaches the dry back end, the surface grips and the ball's side rotation finally does something — it turns. That dashed line across the lane in the game marks where the oil ends.
There is a second effect built in: house shots put more oil in the middle of the lane than at the edges. Send the ball outside and it finds friction sooner, which is exactly why bowlers play the outside line to get the ball back to the pocket.
This is the thing the game is genuinely useful for. Try three shots down the same line:
Neither number is good or bad on its own. It is the ratio between them that produces a repeatable shot, which is why coaches talk about matching speed to revs rather than maximising either. You can measure your own with the ball speed and rev rate calculators.
After each ball the readout shows the angle the ball arrived at. Around 4 to 6 degrees is the range that carries best: enough angle for the ball to drive through the pins rather than deflect off them. A ball arriving straight, near 0 degrees, will knock down plenty of pins and still leave a corner standing more often than it should. That is not bad luck — it is geometry, and it is the single biggest reason a hook outscores a straight ball.
Full ten-frame scoring, bonuses and all: a spare adds your next ball, a strike adds your next two, and the tenth frame gives you the extra balls needed to settle them. If you want the rules laid out properly, the score calculator shows the working.
This is a simplified model. Real ball motion involves axis tilt, rotation, coverstock chemistry, core dynamics, and lane transition as the oil moves during a session. What is modelled here is the part that matters most for understanding why the ball does what it does: oil, friction, revs and speed.