The idea that a concentrated experience of space could offer a direct approach to changes in consciousness led to the construction of a pneumatic space capsule, called the 'Yellow Heart'. Through a lock made of three air rings one arrived at a transparent plastic mattress. Offering just enough space for two people it projected into the centre of a spherical space that was made up of soft, air-filled chambers. Lying there one could perceive that the air-filled "pillows", whose swelling sides almost touched one, slowly withdrew, that is to say the surrounding space appeared to expand, finally forming a translucent sphere and then, in a reverse motion, flowed out again. Large dots arranged in a grid on the outer and inner surfaces of the air-shells changed in rhythmic waves from milky patches to a clear pattern. The space pulsated at extended intervals.