The nested spine +e ( p ( g ( g ) p ) e ) laid as concentric shells and overlaid on the eight-seam box. The observer (electron) is the outer surface; the photon is the messenger; the gluon is confinement; and the centre is not an object but the g|g seam — an even palindrome has no thing at its middle, only a join. Push the nesting to its floor and you land on a seam, which is why the box is all seams.
| electron | box wall / outer face — the surface you touch; the observer's reach |
| photon | the seam channel — signal that crosses in and echoes out |
| gluon | the box interior — confinement; the probe is turned back here |
| g|g seam | dead centre — the one point no seam reaches; sealed core |
| 8 seams | 4 corners + 4 edge-mids ↔ the 8 shell-crossings of a diameter |