Random sequences from alphabet $\{1. \ldots. r\}$ are examined where repeated letters are allowed. Binary search trees are formed from these. https://www.roneverhart.com/HGST-Ultrastar-7K6000-HUS726040ALS214-4TB-7-2K-RPM-SAS-12Gb-s-512n-128MB-3-5-SE-Hard-Drive/