An assembly, in particular compressor or internal combustion engine, has a housing (12) in which there are arranged four pistons (22, 24, 26, 28) of which a first piston (22) has a first end surface (52), a second piston (24) has a second end surface (54), a third piston (26) has a third end surface (56) facing toward the first end surface (52), and a fourth piston (28) has a fourth end surface (58) facing toward the second end surface (54), wherein the pistons (22, 24, 26, 28) are pivotable in reciprocating fashion with limited stroke about a pivot axis (50); a piston cage (90) which is arranged in the housing (12) and in which the four pistons (22, 24, 26, 28) are arranged; a control mechanism (80) in the housing (12), which control mechanism has a cam element (82) on which the pistons (22, 24, 26, 28) are guided in order to generate the pivoting movements thereof, wherein the pistons are rotatable, together with the piston cage or the cam element (82), in the housing (12) about an axis of rotation (88) which is perpendicular to the pivot axis (50), wherein the cam element (82) is arranged radially outside the pistons (22, 24, 26, 28) and annularly around the axis of rotation (88); and working chambers (60; 62; 64; 66) in the housing (12) for in each case one working medium, said working chambers being formed between the end surfaces (52, 56 and 54, 58), which face toward one another, of the pistons (22, 24, 26, 28).; Here, a first and a second working chamber (60, 62) are formed between the first end surface (52) of the first piston (22) and the third end surface (56) of the third piston (26), said first and second working chambers being sealingly separated from one another by a first partition (68), and a third and a fourth working chamber (64, 66) are formed between the second end surface (54) of the second piston (24) and the fourth end surface (58) of the fourth piston (28), said third and fourth working chambers being sealingly separated from one another by a second partition (70).