Fotógrafo - Paulo Bastos; Átrio do Edifício Sede do Tribunal de Contas, Lisboa
Extracted from https://www.uc.pt/ruas/inventory/mainbuildings/matematicas
Extracted from Digital Catalog (Portuguese Catalog), of the Exhibition Portuguese Mathematical Typography from 1496 to 1987
Extracted from the FCT research project UTAustin/MAT/0009/2008
Extracted from the FCT research project PTDC/MAT-NAN/0593/2012
Engineered aluminium sculpture by Wolfgang Buttress :: http://www.wolfgangbuttress.com/#/hive-soundscape-3/
Some small improvements are still being done.