How do I swing higher in a rope swing game?

Pump: hold Shift, the pump button or a second finger as you pass the bottom of the swing, and let go of it near the top. Shortening the rope where it pulls hardest adds real energy, just like standing up on a playground swing.

When is the best time to let go of a swing?

When you are moving up and forward at about 45°. Without air drag that angle gives the longest flight on level ground. The game marks releases between 35° and 55° as Perfect.

What is the formula for a pendulum’s period?

For small swings, T = 2π√(L/g), where L is the length and g is 9.81 m/s². A 1 m pendulum takes about 2 seconds to swing there and back, and the mass doesn’t matter.

Why does pumping a swing work?

Raising your body toward the pivot at the bottom of the swing, where the rope pulls hardest, does work against that pull and adds energy. This is parametric pumping. Rocking your body back and forth also drives the swing, and on playground swings it usually does most of the work.

What did the Foucault pendulum prove?

That the Earth rotates. In 1851 Léon Foucault’s 67 m pendulum in the Panthéon in Paris slowly turned its plane of swing, about 11° an hour, as the Earth turned beneath it.

Is there a daily challenge?

Yes. Tap “daily course” before a run to swing the same seeded course as everyone else today, and try to beat your daily best.

Swing Across

Swing from push pin to push pin across a giant notebook. Let go at just the right moment. Back to the game

How to play

Pip, a small ink acrobat with a long red scarf, stands on a pink eraser taped to a corkboard. Press and hold anywhere (or hold Space) and Pip jumps and fires a rope at the nearest push pin ahead. Keep holding to swing. Let go to fly. While you are in the air, hold again and the rope shoots out at the next pin. A dotted pencil circle shows which pin you would catch.

Fall off the bottom of the board, get snipped by the scissors or caught by the hole punch, and the run is over. Red rubber bands near the bottom are safety nets you can bounce on, and desk fans blow you back up. Paper clips slide along their wires like a zip line. Every few minutes the pages change: a school notebook, a sketchbook at night, a watercolour pad, graph paper and an old map. There is a new course every run, and a daily course that is the same for everyone today.

Your second input is the pump: hold Shift (or the down arrow, the right mouse button, the round pump button, or a second finger). On the rope it shortens the rope, the way you stand up on a swing. In the air it makes Pip tuck into a ball and spin faster.

The physics is real

Pip is a 45 kg point mass on an elastic rope, simulated 240 times a second. Gravity is 9.81 m/s². The rope is a stiff spring that can only pull, so it stretches a few centimetres under load and twangs a little when you catch a pin at speed. The rope pulls along its own length and nowhere else, so swinging trades height for speed and back again, just as in a real pendulum. A rope 4 m long swings there and back in about 4 seconds, since the period of a pendulum is T = 2π√(L/g). Long ropes feel slow and heavy; short ropes are quick.

Air drag uses the real formula F = ½ρv²C_dA, with air density 1.225 kg/m³, a drag coefficient of 1 and about half a square metre of acrobat (less when tucked). At ordinary swinging speeds drag takes only a few percent of your energy, but it adds up, so you can’t keep going forever without adding energy. The fans work the same way: the drag is worked out from your speed relative to the moving air, so a strong updraft can stop a fall.

The perfect release comes from projectile motion. Without air resistance, a launch at 45° goes furthest on level ground, so a release is marked Perfect when you are flying up and forward at between 35° and 55°. The little pencil protractor that appears beside Pip shows your direction of travel while you swing.

Why pumping works

Pumping shortens the rope by up to 30%. Do it as you pass the bottom of the swing, where the rope pulls hardest, and let the rope back out near the top, where it hardly pulls at all. Pulling your weight toward the pin against that big tension is real work, and it goes into the swing. Pulling in also speeds you up, because your angular momentum around the pin stays the same while the radius shrinks. This is called parametric pumping, and it’s how kiiking athletes pump a giant swing all the way over the top while standing. On a playground swing, rocking your body back and forth does even more of the work.

Flips use the same idea. When you let go, Pip keeps spinning at the rate the rope was turning. Tucking cuts Pip’s moment of inertia to about a third, so the spin speeds up to about three times as fast. Every full flip multiplies the points you earned on that flight, as long as you catch the next pin.

Shorten the rope where it pulls hardest, and let go when you are flying up and forward at about 45°.

Tips

Catch a pin when the rope would be sideways to your direction of travel. If you catch it while flying straight away from it, the rope jerks and you lose energy.
Long ropes swing you low. If the floor is coming up fast, pump to shorten the rope.
Pump only at the bottom. Holding the pump all the way round does almost nothing.
Let go a little early rather than late: past the top of the swing you are flying backwards.
Gold pins are rare and worth 1,000 points.

A short history of the pendulum

Galileo began studying pendulums around 1602 and found that a swing keeps nearly the same beat however wide it goes. The story that a swaying lamp in Pisa Cathedral started it comes from his biographer. In 1656 Christiaan Huygens built the first pendulum clock, which cut a clock’s error from about 15 minutes a day to about 15 seconds. In 1851 Léon Foucault hung a 28 kg bob on a 67 m wire in the Panthéon in Paris. Its swing slowly turned, about 11° an hour, which showed that the Earth turns. If you like pendulums, try ../harmonograph/, or throw something far with ../build-a-trebuchet/.

Questions people ask

How do I swing higher in a rope swing game?: Pump: hold Shift, the pump button or a second finger as you pass the bottom of the swing, and let go of it near the top. Shortening the rope where it pulls hardest adds real energy, just like standing up on a playground swing.
When is the best time to let go of a swing?: When you are moving up and forward at about 45°. Without air drag that angle gives the longest flight on level ground. The game marks releases between 35° and 55° as Perfect.
What is the formula for a pendulum’s period?: For small swings, T = 2π√(L/g), where L is the length and g is 9.81 m/s². A 1 m pendulum takes about 2 seconds to swing there and back, and the mass doesn’t matter.
Why does pumping a swing work?: Raising your body toward the pivot at the bottom of the swing, where the rope pulls hardest, does work against that pull and adds energy. This is parametric pumping. Rocking your body back and forth also drives the swing, and on playground swings it usually does most of the work.
What did the Foucault pendulum prove?: That the Earth rotates. In 1851 Léon Foucault’s 67 m pendulum in the Panthéon in Paris slowly turned its plane of swing, about 11° an hour, as the Earth turned beneath it.
Is there a daily challenge?: Yes. Tap “daily course” before a run to swing the same seeded course as everyone else today, and try to beat your daily best.