The Left Angle Cross of Revolution is named for Gate 49 and Gate 4, the same pair as the Cross of Formulization with sun and earth exchanged. Human Design reads Gate 49, from Hexagram 49, Revolution, as the sense of what is acceptable, now the more exposed gate, and Gate 4, from Hexagram 4, Youthful Folly, as the mental urge to supply answers and hypotheses to questions still open. It falls in the Left Angle family, which practitioners read as fated in flavour, serving something beyond the individual rather than a self chosen plan, which is where the cross's name of revolution is read from.
Its design half is Gate 14 and Gate 8, also exchanged in order. Gate 14 sits in the Sacral centre and is read as skilled power, the fuel that directs resources and effort toward worthwhile work; elsewhere it pairs with Gate 2 in the channel of The Beat. Gate 8 sits in the Throat and is read as the urge to contribute an individual style and stand publicly behind something that matters; it pairs with Gate 1 in the channel of Inspiration.
Putting principled rupture ahead of an answering mind changes what this cross puts forward first, while a sacral fuel and an individual contribution sit beneath it regardless of order. Both hexagrams are old texts; pairing them this way as a life direction dates from the system's founding in 1987.