English: Animation of the 1:2:4 Laplace resonance between Io, Europa, and Ganymede. The labels indicate the ratios of orbital periods: Europa's is twice Io's, and Ganymede's is four times Io's.
In this revision of a black and white version, brief color changes are used to highlight conjunctions (green or magenta for nearest-neighbor, gray for non-nearest neighbor), to illustrate that the conjunctions recur at the same orbital locations (after making allowance for precession). All nearest-neighbor conjunctions occur in the vertical axis running through the diagram. Per orbit of Ganymede, there are 8 occasions when at least 3 bodies line up (examples of syzygy), separated by successive intervals of 1/6, 1/6 ,1/12. 1/12, 1/6, 1/6, 1/12 and 1/12 of a cycle, including 2 occasions when all 4 bodies line up (all oppositions of Europa involve 4-body lineups).
Warning: do not downsize the image below its original size of 365 × 245 when used in a Wikipedia article, as the animation won't move then (at least not for all users).