https://people.math.ethz.ch/~acannas/Outreach/ctt_simetria_passo_a_...

... served as main health institution and of medical study in Lisbon for two and a half centuries; • the ... the case of three-dimensional objects) is an axis or plane of symmetry. When the image of half of the ... served as main health institution and of medical study in Lisbon for two and a half centuries; • the ... the case of three-dimensional objects) is an axis or plane of symmetry. When the image of half of the ...