However, it is constructible using neusis, or an angle trisector. It is also constructible with compass, straightedge and angle trisector. Bricard also gave one of the first geometric proofs of Morley's trisector theorem in 1922. The trisector fairing was first used on the DSP-23 flight. All other regular -gons with can be constructed with compass, straightedge and trisector. It can be constructed with an angle trisector, since 13 is a Pierpont prime. However, it can be constructed with an angle trisector, because 7 is a Pierpont prime. The first trio recording, "Trisector", was released on 17 March 2008. Trisector is the tenth studio album by the British rock group Van der Graaf Generator.