In a yearlong process of thinking, sketching and trying he found six possibilities. The 7th possibility was found by the then 15 year old Rein Jansma, son of good friends. This proved to be the first step in the long collaboration between the two which ultimately lead to the foundation of Zwarts & Jansma Architects.
Years later the Technical University Eindhoven realised the cubes as a giveaway for their 50th anniversary. Technical possibilities had improved by then. Moshé Zwarts managed to discover more variations, this time with the aid of the computer, bringing the total to ten.
The question remains whether there are more possibilities - we are looking forward to getting suggestions!
The conditions are:
The four vertical sides of the cube look exactly the same.
The two halves of the cube are completely filled, meaning that the lower half is attached entirely to the upper half.
The two halves can be separated completely from each other.