* Manufactured by Darling Model Kits, this custom kit was designed by T.W.Graham Solomons. * The kit consists of Darling's basic Molecular Vision kit with a few additional pieces, so that p orbitals could be shown in molecules like acetylene. * This customized kit also has pieces that allow linear geometry for the sigma bonds of alkynes while also having orthogonal connections at each atom for the associated p orbitals. * By attaching balls of the right colors it is possible to show the lobes of the p orbitals that make up the pi bonds in an alkyne. * Ball colors can be matched symmetrically to show in-phase orbital overlap, or antisymmetrically to show an antibonding state. * Use of colored balls with the appropriate framework geometry is a very nice feature of the Darling model set. * Pieces from Darling's inorganic model set and are used for octahedral geometry.