What kinds of shapes can it make?

Three families. A polygon is drawn from 3 to 24 corners at uneven angles and distances from the centre, so no two look alike. A star takes the same corner count as points and puts a valley behind each one, which is why a 6 corner star has 12 vertices on its path. A blob averages each radius with its two neighbours, so the outline rolls instead of spiking. One sheet holds 1 to 24 shapes, each drawn inside its own canvas of 40 to 2000 pixels a side, and the corner range can be pinned to one number if you want every shape to have the same count.

Can I get the same shapes again tomorrow?

Keep the seed. Any whole number from 0 to 999999 decides the sheet, and the same seed with the same family, corner range, symmetry, curvature and canvas redraws the same shapes to the pixel, on any machine. Each shape is drawn from a stream of its own, seeded from the seed and the shape's position, so raising the count from six to nine leaves the first six exactly as they were and adds three. The seed is shown on the page and in the file name of every download. It is deliberately not remembered between visits, so each visit opens on new shapes unless you type a seed back in.

How do I get the shapes out of the page?

Three ways, none of them gated. Copy puts the whole sheet on the clipboard as SVG markup you can paste into a design tool or an HTML file. Download SVG saves the same markup as a file: one tile a shape, each path carrying its own canvas coordinates, with no size limit. Download PNG rasterises that sheet in your browser at the sheet's own pixel size, up to 4096 pixels a side; past that the tool says so and points you at the SVG instead of quietly shrinking anything. The vertex coordinates are listed under the sheet as plain text, ready to paste into code or a worksheet.

What does the mirror setting do?

It folds the shape about the middle of its canvas, rounded to a whole pixel, either the vertical axis (left matches right) or the horizontal one (top matches bottom). The mirrored half is the reflection of the rounded coordinates, not a second set of numbers that nearly agree, so the pairs are exact: a mirrored 8 corner polygon is 4 mirrored pairs and nothing on the axis. An odd corner count cannot split evenly, so one vertex sits on the axis and the rest pair up; a star always puts two on the axis so its points and valleys keep alternating. Turn the mirror off and every corner is drawn on its own.

What is curvature, and does it move the corners?

Curvature is how far each corner is cut back along both of its sides before an arc is drawn across it. Straight is 0.00 and leaves the corner sharp, soft is 0.35, smooth is 0.70, and mixed gives each shape on the sheet one of those three, drawn from the seed. The corner itself is the control point of the arc, and curvature is drawn from a separate stream, so switching from straight to soft rounds every corner without moving a single vertex: the coordinates under the sheet do not move. An arc always stays inside the triangle its corner makes, so a rounded shape cannot leave the canvas either.

Can I use these shapes in a class, a worksheet or a design?

Yes. The geometry is generated here from your settings rather than taken from a picture library, so a sheet of shapes for a drawing warm-up, a symmetry lesson, a cutting template or a placeholder graphic is yours to print, trace or edit. Mirror on with a fixed corner count makes a set of symmetry exercises that are all different but all provably symmetric, and the bounding box printed on each shape's line tells you how much of the canvas it fills before you print.

Random Shape Generator

Press Draw again and this fills a sheet with closed geometric shapes built here in your browser: polygons with straight sides, stars with a valley behind every point, and blobs whose radii are averaged with their neighbours so the outline rolls. You set the family, how many shapes (1 to 24), how many corners each one may take (3 to 24), the canvas each shape sits in (40 to 2000 pixels a side), whether it is mirrored, and how far the corners are cut into arcs. Two things separate this from the shape pages that hand you a picture: every shape is generated geometry rather than a stored image, and every number behind it is on the page. The seed (0 to 999999) redraws the same sheet exactly, the panel under the shapes lists each one's vertex count, curvature and bounding box, and the coordinate list under the sheet holds the same whole-pixel vertices the SVG export carries. Nothing is uploaded and nothing is gated.

6 shapes
Polygon 5 to 9
Mirror on
Seed 771

canvas     480 x 480 px        seed 771
family     polygon             corners 5 to 9
symmetry   mirror, vertical axis
curves     mixed, 0.00 or 0.35 or 0.70 a shape

shape 1    7 vertices    curvature 0.35    bbox 35,21 to 445,366
shape 2    8 vertices    curvature 0.00    bbox 43,53 to 437,440
shape 3    9 vertices    curvature 0.00    bbox 44,27 to 436,403
shape 4    8 vertices    curvature 0.70    bbox 54,48 to 426,415
shape 5    5 vertices    curvature 0.00    bbox 84,98 to 396,386
shape 6    9 vertices    curvature 0.35    bbox 60,33 to 420,419

all paths closed, all inside the canvas

Shapes

Canvas

Symmetry

Seed

Family

Corners

Curvature

6 polygon shapes, 46 vertices in all, on seed 771 in a 480 by 480 canvas. Every path is closed and every point is inside the canvas. 21 mirrored pairs about the vertical axis.

Press Space or Draw again for a fresh seed. Every shape is a closed path built around the middle of its own canvas, rounded to whole pixels and held inside it, so a sheet is safe to print, cut or trace. Copy puts the whole sheet on the clipboard as SVG; Download SVG saves the same markup, one tile a shape; Download PNG rasterises it here in your browser. The family, the counts, the canvas and the two settings are kept in this browser so the page opens where you left it, and Start over at the top of the page forgets them. The seed is not kept, so every visit begins with new shapes.

Vertex coordinates, the numbers the SVG carries

Each shape sits in its own 480 x 480 canvas, in whole pixels, and these are the numbers the SVG carries.

shape 1, 7 vertices, curvature 0.35
240,21 361,108 445,258 300,366 180,366 35,258 119,108

shape 2, 8 vertices, curvature 0.00
285,53 388,193 437,300 319,440 161,440 43,300 92,193 195,53

shape 3, 9 vertices, curvature 0.00
240,27 339,78 436,182 406,352 314,403 166,403 74,352 44,182 141,78

shape 4, 8 vertices, curvature 0.70
325,48 379,214 426,320 279,415 201,415 54,320 101,214 155,48

shape 5, 5 vertices, curvature 0.00
240,98 396,104 374,386 106,386 84,104

shape 6, 9 vertices, curvature 0.35
240,33 319,116 420,198 395,383 318,419 162,419 85,383 60,198 161,116

Seed 771same settings
the same 6 shapes, exactly
Mirror on, 8 cornersvertical axis
4 mirrored pairs
Curvature 0.35the same vertices
the same 8 vertices, 8 corner arcs

Accuracy. Shapes are generated from the seed and the bounds you set, and every path is closed and clipped so no vertex leaves the canvas. The same seed and settings redraw the same sheet, and the SVG export carries exactly the vertex coordinates shown, so a shape you like can be reproduced later. Coordinates are whole pixels: each corner is placed, rounded, then held inside the canvas, and every sheet is read back off its own paths before the page prints the line under it.

Common questions

What kinds of shapes can it make?: Three families. A polygon is drawn from 3 to 24 corners at uneven angles and distances from the centre, so no two look alike. A star takes the same corner count as points and puts a valley behind each one, which is why a 6 corner star has 12 vertices on its path. A blob averages each radius with its two neighbours, so the outline rolls instead of spiking. One sheet holds 1 to 24 shapes, each drawn inside its own canvas of 40 to 2000 pixels a side, and the corner range can be pinned to one number if you want every shape to have the same count.
Can I get the same shapes again tomorrow?: Keep the seed. Any whole number from 0 to 999999 decides the sheet, and the same seed with the same family, corner range, symmetry, curvature and canvas redraws the same shapes to the pixel, on any machine. Each shape is drawn from a stream of its own, seeded from the seed and the shape's position, so raising the count from six to nine leaves the first six exactly as they were and adds three. The seed is shown on the page and in the file name of every download. It is deliberately not remembered between visits, so each visit opens on new shapes unless you type a seed back in.
How do I get the shapes out of the page?: Three ways, none of them gated. Copy puts the whole sheet on the clipboard as SVG markup you can paste into a design tool or an HTML file. Download SVG saves the same markup as a file: one tile a shape, each path carrying its own canvas coordinates, with no size limit. Download PNG rasterises that sheet in your browser at the sheet's own pixel size, up to 4096 pixels a side; past that the tool says so and points you at the SVG instead of quietly shrinking anything. The vertex coordinates are listed under the sheet as plain text, ready to paste into code or a worksheet.
What does the mirror setting do?: It folds the shape about the middle of its canvas, rounded to a whole pixel, either the vertical axis (left matches right) or the horizontal one (top matches bottom). The mirrored half is the reflection of the rounded coordinates, not a second set of numbers that nearly agree, so the pairs are exact: a mirrored 8 corner polygon is 4 mirrored pairs and nothing on the axis. An odd corner count cannot split evenly, so one vertex sits on the axis and the rest pair up; a star always puts two on the axis so its points and valleys keep alternating. Turn the mirror off and every corner is drawn on its own.
What is curvature, and does it move the corners?: Curvature is how far each corner is cut back along both of its sides before an arc is drawn across it. Straight is 0.00 and leaves the corner sharp, soft is 0.35, smooth is 0.70, and mixed gives each shape on the sheet one of those three, drawn from the seed. The corner itself is the control point of the arc, and curvature is drawn from a separate stream, so switching from straight to soft rounds every corner without moving a single vertex: the coordinates under the sheet do not move. An arc always stays inside the triangle its corner makes, so a rounded shape cannot leave the canvas either.
Is anything uploaded, and does it remember my settings?: Nothing leaves the page. The shapes are computed in your browser from the seed, and no drawing, setting or coordinate is sent anywhere. The family, the counts, the canvas size, the symmetry and the curvature are kept in this browser so the page opens where you left it, and Start over at the top of the page forgets them. The seed is not kept, so you get new shapes on the next visit. If your browser blocks storage, the tool still draws: it simply opens on its own defaults every time.
Can I use these shapes in a class, a worksheet or a design?: Yes. The geometry is generated here from your settings rather than taken from a picture library, so a sheet of shapes for a drawing warm-up, a symmetry lesson, a cutting template or a placeholder graphic is yours to print, trace or edit. Mirror on with a fixed corner count makes a set of symmetry exercises that are all different but all provably symmetric, and the bounding box printed on each shape's line tells you how much of the canvas it fills before you print.

Shapes are generated from the seed and the bounds you set, and every path is closed and clipped so no vertex leaves the canvas. The same seed and settings redraw the same sheet, and the SVG export carries exactly the vertex coordinates shown, so a shape you like can be reproduced later.