My 1st idea is inventing cube-shaped 3-dimensional liquid crystal monitors working on the principle of overlapping electromagnetic waves of different frequences projected into a transparent tank of wave-sensitive liquid crystals. It would show realistic three-dimensional objects of crystals coloring under the influence of crossing em-waves. These shapes could be observed from any of 6 flat sides of such 3D displays.
My 2nd idea is inventing a special triaxial manipulator for steering these 3D shapes. It would be able to move in 3 dimensions directed by user's hand. In order to work effectively this manipulator is going to consist of a movable element fitting user's hand conveniently and 2 scanners, which would determine its position in 3D space and follow its movements. The scanners can be either usual optical or ultrasound ones.