Geoff Giles died suddenly in 2005. He was a highly original thinker in the field of geometry teaching. As early as 1964, when teaching at Strathallen School in Perth, he was writing in "MT27" about constructing tessellations by modifying the sides of triangles and (irregular) quadrilaterals to produce what he called "trisides" and "quadrisides". In his memory, the author ran a seminar at a 2007 conference. He describes this here, with quotations from Giles' writings. (Contains 27 figures.)