About: http://webisa.webdatacommons.org/292435476

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	In the plane of the light beam, i.e. of the incident and reflected radiation 32, 16 with respect to the mirror 36, the mirror 36 must tilt an amount equal to half the tool tilt to ensure that the projected beam 16 remains vertical.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com