Caroline Delbert.Germans Are Building a Time Pyramid Over the Next 1,000 Years. They should probably hurry up. (амер. англ.). Popular Mechanics (29 мая 2020). — «The pyramid has four tiers and is made of even-number squares: 8×8, 6×6, 4×4, and finally 2×2 at the apex. After the first 640 years, builders will need to place additional blocks on top of existing ones.» Дата обращения: 10 мая 2023. Архивировано 15 марта 2023 года.
Caroline Delbert.Germans Are Building a Time Pyramid Over the Next 1,000 Years. They should probably hurry up. (амер. англ.). Popular Mechanics (29 мая 2020). — «The pyramid has four tiers and is made of even-number squares: 8×8, 6×6, 4×4, and finally 2×2 at the apex. After the first 640 years, builders will need to place additional blocks on top of existing ones.» Дата обращения: 10 мая 2023. Архивировано 15 марта 2023 года.
