Abstract: A dry-erase ink is disclosed for writing or marking on glossy and non-porous surfaces, in particular whiteboards or dry-erase boards, which ink is wipeable or erasable after drying without leaving visible colored residues. The ink contains a solvent, one or more dye(s) soluble in the solvent, a film forming resin such as polyvinylpyrrolidone or a derivative thereof, a strongly-alkaline substance such as a diamine and/or a quaternary organic ammonium hydroxide, an organic acid or a salt thereof and, if desired, a nonvolatile, liquid component serving as a release agent.

Abstract: An improved planning purpose display device includes a board bearing a display surface with an electrically isolated matrix of conductors embedded therein, with the display surface having at least one hole at each intersection of conductors. A plurality of LCD display elements are conductively mountable in the holes of the display surface, and each LCD display element is controllable by a microprocessor therein. A computer connected to the conductors is adapted to communicate with the LCD display elements mounted on the display surface, interrogate each LCD display element with respect to its position on the display surface, the contents of the memory of its microprocessor and/or to program the memory of that microprocessor.