(IMAGE) University of Liège Caption Problem description. (a) Random stacking process (b) Description of block positions (c) Illustration of the position of the centre of gravity of the upper part of the tower above level 3 (𝑛 = 6, 𝑖 = 4). Credit Université de Liège / V. Denoël Usage Restrictions No commercial use License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.