How to play Fair Slice
Fair Slice is a cut it in half drawing game that tests how well you can judge area by eye. Each level shows one shape: a slab of cake, a pizza, a star, a heart, a moon or an awkward L-shaped block. Draw one straight line through it and the game slices it, pulls the pieces apart and tells you exactly what share of the area landed on each side. Get close enough to 50 / 50 and you pass.
- Press outside the shape where you want your cut to start.
- Drag across the shape. A dashed red line shows your knife.
- Let go outside the shape on the other side.
- Read your result: the closer to an even split, the higher the score.
- From level 21, make two cuts to share the shape into three equal pieces.
Tips for a perfect split
- Aim through the balance point. A straight cut that halves a shape always passes close to its centre of mass. Imagine where the shape would balance on a fingertip and cut through that spot.
- Pick an easy direction. You can cut at any angle. Choose one where the two halves look alike, for example across the narrow part of a long shape, so it is easier to compare them.
- Fat parts count more than long parts. Thin spikes of a star or the horns of a moon look big but hold little area. Compare the chunky middle sections instead.
- Use parallel cuts for thirds. On two-cut levels, two parallel lines are the simplest way to get three pieces. Make the outer pieces visibly smaller than half of what is left.
- Learn from the numbers. If your left side scored 53%, shift the next cut a little towards it. Your eye improves quickly with feedback.
A fair-sharing skill game
Splitting something fairly is an everyday problem: sharing a pizza, a bar of chocolate or a slice of cake. Mathematicians have a neat result about it called the ham sandwich theorem, which says any two shapes can always be halved at the same time by a single straight cut. For one shape there is a perfect halving line in every direction you choose, so a 100% cut is always possible. The hard part is seeing it. Our eyes are good at judging lengths but surprisingly bad at judging areas, especially for irregular and concave shapes, which is exactly what makes this game addictive.
Levels and scoring
There are 30 levels. The first ones are friendly shapes such as a rectangle, a circle and a wedge. Then come blobs, stars, hearts, crescents, bones and stepped blocks in random rotations. Levels 21 to 30 need two cuts and three equal pieces, which is far harder than it sounds. Areas are calculated exactly from the outline of the shape, not estimated from pixels, so the percentages you see are precise. Your best stars are saved on this device.
How to get better at judging area
Most people start out cutting through the middle of the bounding box, which works for symmetrical shapes but fails badly on hearts, moons and L-shaped blocks. A good habit is to look at the shape for a few seconds before drawing and mentally fold it along your planned line: do the two halves look like they would cover each other? The pieces are pulled apart and labelled after every cut, so you get exact feedback on which side was too big. Play a few rounds and you will notice your estimates getting sharper, which is a fun way to train spatial judgement.
Want more precision challenges? See how round you can go inDraw a Perfect Circle, or switch to logic withOne Line Draw Puzzle.
Fair Slice FAQ
How do you play Cut It in Half?
Drag a straight line across the shape with your mouse or finger. Start outside the shape and finish outside it on the other side. When you let go, the shape is cut along your line and the game shows the exact percentage of area on each side.
How is the accuracy score calculated?
The game measures the exact area of every piece. A perfect 50 / 50 split scores 100%. Every percentage point that one half is bigger than the other costs two points, so a 48 / 52 cut scores 96%. With three pieces, the piece furthest from one third decides the score.
What score do I need to pass a level?
Single cuts need at least 90% accuracy, which means both halves are within 45 / 55. For three stars you need 97% or better. Two-cut levels need 85% to pass and 95% for three stars.
Why was my cut rejected?
A cut has to go all the way through the shape: both ends of your line must be outside it, and on concave shapes it must not stop inside a gap. On two-cut levels the two lines also may not cross inside the shape. Rejected cuts do not count, so just try again.
Does the length of my drag matter?
Only the direction and position matter. The line runs straight from where you pressed to where you let go, however wobbly your hand moved in between, so you can take your time to aim.
Can I play on mobile and is it free?
Yes. It works with touch on phones and tablets and with a mouse on computers. It is free, needs no download or sign-up, and your stars are saved in your browser.