A whole wall of glass blocks can be created to cover the knee wall. The solid wall consists of glass blocks mortared together. Check the strength of your floor. It might need to be reinforced to support the weight of the glass blocks, depending on how long and tall the wall is. Because glass blocks cannot be cut, you might have some space between the top of the wall and the ceiling. Set silk plants on top or decorative items as you would on a shelf.
Instead of creating a solid wall, build a stepped wall in the knee wall area. Cover the bottom part with a row of glass blocks. The second row will be mortared onto the first but it should be one to three blocks shorter in length than the bottom layer. Build up one or two more layers for the knee wall, with each layer shorter than the layer below it to give the wall a stepped appearance on one edge.
Use glass paints to add pictures to the glass blocks you use to build a knee wall. Paint small images to match the rest of the decor of the room. For instance, if you have a room with modern furnishings, try simple geometric shapes painted on the glass blocks in colors to match the furniture. To add more color, install colored glass blocks in the knee wall interspersed with clear blocks. The combination of clear and colored blocks will keep the colored blocks from being too overwhelming.
Low voltage fiber optic lights installed behind a knee wall made of glass blocks can brighten the space. The lights will shine through the glass and be diffused by the shape of the glass. The knee wall will have a subtle glow. Use colored lights for a colorful accent to your room.