Creating A custom curve in vb

I'm trying to create a program that will draw a line based on a key press that will represent the movements of a remote control car. I have the 90 degree angles drawing but when the car turns it obviously doesn't turn in 90 degree angles. Is there a way i can make a curve that draws at a set angle? I thought about also getting the program to accept two key inputs simultaneously and using those keys to trigger the turn so that it works forward and backward but couldn't get vb to accept two keyboard inputs simultaneously. It gives priority to the last hit key. any ideas?