sketch = svg`<svg viewBox=${[0, 0, dimensions.width, dimensions.height]}
width=${dimensions.width}
height=${dimensions.height}>
<rect
width=${dimensions.width}
height=${dimensions.height}
fill=${palette.bg}></rect>
<circle
cx=${math.lerp(0, dimensions.width, uv[0])}
cy=${math.lerp(0, dimensions.height, uv[1])}
r=10></circle>
</svg>`