| 摘要 |
An educational device having an enclosed housing formed of a vessel-like base and a substantially flat transparent top the edges of which sealingly engage upper edges of the base. The housing is substantially filled with liquids. A divider is carried within the housing adjacent the top. The divider comprises mutually perpendicular vertical walls defining an array of bottom opening compartments which, when viewed through the top, are arrayed in mutually perpendicular rows and columns. A plurality of buoyant ball members, having distinctive indicia thereon, are carried in the housing.
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