頻次

频 = 步 + 页 : Pocahontas (pi) is repeatedly (频) shaking a five-paced viper (步) in the encampment's kitchen ((e)n2). She wants to find out the eigenfrequency (频) of the viper by shaking it at different holding points. She marks her findings on a sheet of paper (页), and next to her she stores a whole stack of papers (页) she already published on the subject.

次 = 冫 + 欠 : Mnemonic symbol: the cube, as in words involving 三次 relate to "cubic equations" or "cube (third power)". The King of Chu (c) pulls a popsicle (冫) out of the cube (次) in the space station's bathroom (Ø4) and leaves an IOU note (欠) on the cube.