Make a kaleidoscope photo

A kaleidoscope is a set of mirrors meeting at a point, and the picture you see depends on how many there are and at what angle. Four-way is two mirrors at right angles: one quarter of your photo is kept as it is and reflected into the other three, so the result is symmetric left to right and top to bottom. Diagonal is a single mirror running corner to corner across a square, which makes the top-right triangle the reflection of the bottom-left. Wedges are the toy itself: a slice of the photo, cut at the centre point, is repeated six or eight times round a circle with every other copy reflected, so the edges meet.

The first two are exact — every pixel in the result is a copy of one in your photo, moved to a whole-pixel position. Wedges need copies turned by 60° or 45°, which lands between pixels, so the page says the result is resampled. The centre is yours to move in every kind: drag the point on the picture or type the percentages, and the pattern regrows from whatever sits there.

1. 1Open a photo. Flowers, foliage, architecture and textiles make strong patterns; faces make strange ones.
2. 2Choose the kind. Four-way keeps one quarter and reflects it into the others. Diagonal reflects a square across its corner-to-corner line. Wedges repeat a slice six or eight times round a circle.
3. 3Move the centre. Drag the point on the picture, or type percentages. The pattern grows out of whatever sits nearest the centre.
4. 4Make it tile, and save. With the centre at 50 %, a four-way result repeats without a seam — the preview shows it 2 × 2. Save as PNG for a pattern you can repeat anywhere.

A 3000 × 2000 photo of a flowerbed with four-way from the top-left quarter and the centre at 50 % gives a 3000 × 2000 result whose top-left 1500 × 1000 block is the photo’s own. Move the centre to 30 % across and 40 % down and the kept quarter becomes 900 × 800, so the result is 1800 × 1600. The diagonal kind cuts the centred 2000 × 2000 square. Eight wedges give a 2000 × 2000 square too, with the corners outside the circle filled as you choose.

• Moving the centre changes the size. The four-way result is twice the kept quarter in each direction, so an off-centre point makes a smaller picture.
• Wedges resample. Copies turned by 60° or 45° are interpolated. Four-way and diagonal are exact.
• Only four-way at 50 % tiles cleanly. Wedge patterns are round and diagonal ones are square-cut; neither repeats without a visible edge.

What is the difference between four-way and wedges?

Four-way uses two straight mirrors at right angles, so every pixel is an exact copy and the result is a rectangle. Wedges imitate a real kaleidoscope's angled mirrors: a slice of the picture is repeated round a circle, every other copy reflected. Turning by 60° or 45° lands between pixels, so wedges are resampled; four-way and diagonal are not.

How do I make a seamless pattern?

Use four-way with the centre at 50 %. Each edge of the result is then the mirror of the opposite edge's neighbour, so tiles placed side by side meet without a join. The 2 × 2 preview under the controls shows it before you save.

Why is my diagonal kaleidoscope square?

A diagonal mirror only makes sense on a square: the line runs corner to corner. A rectangular photo is cut to its centred square first, and the controls say how big that square is.

Can I choose which quarter is kept?

Yes — top left, top right, bottom left or bottom right. The kept quarter is copied exactly and reflected into the other three.