The Juxtaposition Cross of Behavior carries the same named pair as the Left Angle Cross of Prevention, Gate 10 and Gate 15, with sun and earth exchanged and read here inside the fixed Juxtaposition family. Human Design reads Gate 10, from Hexagram 10, Treading, as behaviour that stays true to one's own nature rather than to expectation, and Gate 15, from Hexagram 15, Modesty, as a love of humanity broad enough to embrace extremes, with no fixed rhythm. Juxtaposition Crosses are set apart from the Right Angle and Left Angle families, reserved for the four line one profile, and read as fixed almost past the point of alternative.
Its design half is Gate 18 and Gate 17. Gate 18 sits in the Spleen and is read as an instinctive alertness to what is flawed and could be set right; elsewhere it pairs with Gate 58 in the channel of Judgement. Gate 17 sits in the Ajna and is read as the forming of opinions that want to be organised and offered to others; it pairs with Gate 62 in the channel of Acceptance.
Where the Left Angle reading of these same gates serves prevention on behalf of others, the Juxtaposition reading holds conduct and tolerance as fixed traits rather than a role assigned. The hexagrams are ancient; grouping them into one incarnation cross is the modern system's own construction.