Maybe a quarter of the raytraced scene. The sphere is noticeably taller than it ought to be. https://media.mstdn.social/media_attachments/files/111/762/936/617/341/997/original/0210ced9e79fff94.png
@bbcmicrobot @coprolite9000 @arx Two hours, and it is apparent that the Electron's aspect ratio is slightly taller than the BBC's. I guess they don't want to keep the CPU halted longer than 40 µs if they can avoid it...