Some tiles associated with the 6th unit cubic Pisot number

Partial Postcomposition Tiles

IV. Partial Postcomposition Derivatives of External Tiles

In addition to the symmetric, demisymmetric and windowed tiles there are (at least) four other order 3 6th unit cubic tiles, including two “external” tiles. As a 3 element tile potentially has 6 partial postautocomposition derivatives, 3 of order 5 and 3 of order 7, these two tiles give rise to 12 candidate attractors. However 4 of these are not connected, leaving 8 tiles - 5 order 5 tiles and 3 order 7 tiles.

The first external tile gives rise to 2 order 5 tiles and 1 order 7 tile. The order 5 tiles have the dissection polynomial c+2c2+c3+c4.

order 5 metaexternal tileorder 5 metaexternal tile

The minimal unit cells have 2 copies of the tile. When the IFS for the tile is { p→-ap + 1; p→-ap - 1; p→-a3p - 1 + a + 3a2 } the cell transforms for the first are { pp; p→-ap - 1 } and for the second are { pp; p→-ap + 1 }, giving a signature in both cases of 01.

order 5 metatile order 5 metatile

The order 7 tile has the dissection polynomial 4c2+c3+2c4.

order 7 metatile

The minimal unit cell (shown below) contains 3 copies of the tile, with a signature of 011. The cell transforms are { pp; p→-ap - 1; p→-ap + 1 }.

order 7 metatile

The second external tile gives rise to 3 order 5 tiles and 2 order 7 tiles. Two order 5 tiles have the dissection polynomial c+2c2+c3+c4; the 3rd 2c+2c3+c5.

order 5 metatile order 5 metatileorder 5 metatile

The minimal unit cells have 2 copies of the tile. When the IFS for the tile is { p→-ap + 1; p→-ap - 1; p→-a3p - 1 + a + 3a2 } the cell transforms for the first are { pp; p→-ap - 1 }, for the second { pp; p→-ap + 1 }, and for the third { pp; p→-a3p - 1 + a + 3a2 }

order 5 metatileorder 5 metatileorder 5 metatile

The order 7 tiles have the dissection polynomials 4c2+c3+2c4 and c+2c2+3c4+c6.

order 7 metatileorder 7 metatile

They both have 3 copies in the unit cell, with signatures 011 and 013 respectively

order 7 metatileorder 7 metatile

© 2015, 2016, 2017 Stewart R. Hinsley