Beitr\"age zur Algebra und Geometrie Contributions to Algebra and Geometry Volume 37 (1996), No. 1, 51-65. On-Line q-adic Covering by the Method of the n-th Segment and its Application to On-Line Covering by Cubes Janusz Januszewski, Marek Lassak, G\"unter Rote, Gerhard Woeginger Abstract. We prove that in Euclidean $d$-space every sequence of cubes with total volume $2^d+3$ is able to cover on-line the unit cube. The proof is based on an on-line $q$-adic method of covering the unit segment by segments of lengths of the form $q^{-r}$, where $q\ge2$ and $r\ge1$ are integers. The fact that this method is $q$-adic means that every segment has to be placed in such a way that both end-points are at points that are multiples of the length of the segment. MSC 1991: 52C17, 68Q20