The Right Angle Cross of Penetration is named for Gate 51 and Gate 57. Human Design reads Gate 51, from Hexagram 51, The Arousing, as competitive courage that goes first and can startle others awake, and Gate 57, from Hexagram 57, The Gentle, as intuition in the present moment, read through hearing rather than sight. It falls in the Right Angle family, and practitioners describe that group as the personal one, a direction shaped by what the individual decides.
Its design half is Gate 54 and Gate 53, both seated in the Root. Gate 54 is read as ambition, the drive to rise, be recognised and transform one's material circumstances; elsewhere it pairs with Gate 32 in the channel of Transformation. Gate 53 is read as the pressure to begin, an impulse that starts new cycles and often has no interest in seeing them through; it pairs with Gate 42 in the channel of Maturation.
So a chart carrying this cross meets shock with intuitive clarity on its exposed surface, Gate 51 answering to Gate 57, while beneath it a Root pair of ambition and the pressure to begin drives what the surface only initiates. The numbers are inherited from the I Ching; reading them as one cross belongs to the modern reading, not the classical one.