Looks like you don't have a clear understanding of what you can do in each type shader. You don't need a geometry shader to do this, a vertex shader is enough.

I suggest you to have a look at this tutorial that shows how to draw triangles in modern OpenGL. Once you understand how you can draw, play with the function void CGLRenderer::SetData(), which is where you set the actual vertex positions of your primitives. What you probably want to do is modify the Vertex Buffer Object content depending on the key that you press.

Looks like you don't have a clear understanding of what you can do in each type shader. You don't need a geometry shader to do this, a vertex shader is enough.

I suggest you to have a look at this tutorial that shows how to draw triangles in modern OpenGL. Once you understand how you can draw, play with the function void CGLRenderer::SetData(), which is where you set the actual vertex positions of your primitives. What you probably want to do is modify the Vertex Buffer Object content depending on the key that you press, this will change the position/orientation/size of your shapes.

Perhaps this is another good tutorial for you. It shows how to create a spinning triangle in WebGL using fragment and vertex shaders. See the result here.