Fig. 2: The Antechamber was a pulley-like system.

a 3D-representation of the Antechamber with the different levels with individual architectural features superposed for clarity (3D-drawing based on measurements and representations from: Plate X in Piazzi Smyth, Our Inheritance in the Great Pyramid. 3rd, new and enlarged edition. London 1874³¹, and Tavola 7 in Vito Maragioglio, L’Architettura delle Piramidi Menfite, Part IV, Roma 1965⁹). b 3D-representation of the Antechamber with wood-logs, looking onto the South- and West-walls with the North and East walls omitted for clarity. c 3D-representation of the Antechamber with wood-logs and a hypothetical arrangement of ropes. Given the four rope-guidance grooves in the South-wall, a system of 4 parallel ropes (colored red, blue, yellow and green) is suggested. The use of 4 parallel ropes distributes the heavy weight of the blocks, up to ~60 tons, to be lifted. d Relative location of the Antechamber pulley-like system with regard to the Grand Gallery and the King’s Chamber. Note, the perfect fit of the rope(s) (red) descending from the first wood-log with an identical slope as the Grand Gallery, 26.5°, into the sliding-ramp. The ‘big step’ at the South side of the Grand Gallery (black arrow) is in the center of the North-South axis, and above the center of the Queen’s Chamber. Defining the center wood-log as the center of the pulley-like system, the center of the mechanism is ~4.87 m South of the ‘big step’ at the end of the Grand Gallery and ~3.52 m North of the King’s Chamber. Illustrating the pulley-like system in the current architectural setting may appear contradictory; however, the Grand Gallery’s upper end and the floor of the Antechamber were open until the later stage of construction. e Use of the upper slab with the boss of the Granite Leaf to stop rope movement during counter-weight reset in the Grand Gallery, when the pulley-like system was operated in gear 4. f Possible configurations of ropes in the pulley-like system: To effectively divide the pulling force by a factor of 4, in order to lift the ~60 tons heavy blocks, the pulley-like system might have been operated in gear 4 (top), while for the majority of ‘normal’ building blocks, the pulley-like system was likely operated in gear 2, where in order to lift a block by height Δh, the length l of rope to be pulled is 2·Δh, perfectly matched with a sliding-ramp with slope 1 cubit over 2 cubits (Movie S1).