The phrase "a stack of four" is correct and usable in written English.
It can be used to describe a quantity or arrangement of four items that are stacked on top of each other.
Example: "She placed a stack of four books on the table, ready to be read."
Alternatives: "a pile of four" or "a group of four".
A first prototype MLI device featuring a stack of four detection layers was used for model validation.
A robot consisting of a stack of four cubes begins by bending over and depositing one of its cubes on the table.
The first approach is used to investigate the stability of both a single isotensoid and a stack of four isotensoids, for perturbations of infinitesimally small amplitude.
The vessel is cylindrical in shape with a stack of four 45 pitched blade impellers, four rectangular side-wall baffles and an ellipsoidal shaped bottom.
A stack of four rectangular, acrylic frames separated by layers of flexible, high-strength rubber was used to form the transparent container.
The spiral, intended to rise higher than the Eiffel Tower, wraps around a stack of four geometric buildings — a cube, a pyramid, a cylinder and a hemisphere — each meant to rotate at a yearly, monthly, weekly or daily rate.
Before every bilateral meeting with foreign officials, Mr. Gore gets the benefit of Mr. Fuerth's deeply detailed knowledge of policy, detailed in thick briefing books and then distilled on a stack of four- by six-inch cards.
Their conflagration is balanced on the right by a stack of two blues and a black.
A stack of three huge pancakes is $5.25, a plate-swallowing pecan waffle is $4.75.
The show feels like a stack of three commercial gallery exhibitions or museum project shows.
We have then a stack of three white spheres that signify archetypal "winter" quite clearly.
