Escheresque

Upload, paste (Ctrl/Cmd+V while hovering here), or pick an example. One corner image gets rotated 0°/90°/180°/270° around a shared center to build one pinwheel-symmetric 2×2 block, then repeated by translation.

Hidden A/B experiment, desktop only. Crop a tileable region from an image, blend its edges for a seamless repeat, then derive a small set of texture maps from it — base color, normal, height, ambient occlusion, and opacity. These are image-derived approximations (built from luminance, contrast, and local gradients), not a physical material scan — brightness isn't real depth. Everything lines up pixel-for-pixel since every map is generated from the same blended base.

Draw one tile by hand. B brushes, E erases, [ / ] resize the brush. The dashed red line always marks the full tile bounds — this view never zooms. Click "Expand" to draw in a larger popup version of the same tile; click the X to close it. "Plain" is a straight repeat; "Corner-block" is section 2's rotational symmetry — draw near the bottom-right corner, since that's the copy that stays unrotated; "Mirror" switches to two separate drawing surfaces below — draw on either one and it paints its own live reflection across the dashed blue axis line, like an inkblot. Export PNG in Mirror mode downloads those two canvases directly rather than a tiled grid.

Click the color view to drop heat points; drag an existing one to move it, double-click to remove it. Distance wraps around the tile edges (not just straight-line distance), so a point near one edge also warms the opposite edge — that's what makes the heat field itself tile seamlessly. Both views share the same points, and either one is clickable — drop, drag, or double-click to remove a point on whichever view you prefer. [ / ] adjust the radius that gets applied to the next point you place.