Unofficial: On 2nd turn, 4c has an easier start if 1c+3c+4c dance a 3c Poussette
This dance is a fugue; the M copy the W 8 bars later.
3c+4c cross on 2nd chord (1,2,3x,4x). Centro-symmetrical dance.
3C Chain Progression was earlier known as Chaperoned Chain Progression
Note: on  the original says »RH«, but »BH« is widely used.