Lighting: The first way to incorporate geometric shapes into your bathroom space is the lighting you use. You could use any type of hanging pendant light that offers some sort of geometric shape. Maybe something that is a three tier square shape that hangs down from the center of the bathroom? Even a cool, funky star shape hanging down from the ceiling would work too. I understand though not everyone is a fan of pendant lighting in the bathroom so if you are not a fan, try adding rectangular lights on the side of your mirrors over the vanity. This way you still have some sort of geometric space to go along with your modern theme. I highly recommend LED lights for any lighting source you do go with because it will offer a higher amount of light throughout the space.
Bath Tub: If you are trying to achieve the geometrical shape theme in your master bathroom and you have a bathtub, that is a fun way to add extra shapes throughout the space. You might have to leave the claw foot tub out in this style, but you can add a square tub that sits off by itself so that people can really see the full shape and clean lines of the tub. Or if you are more interested in an oval shape tub you could go with that style too. I recommend the bathtub being some sort of focal point in the bathroom, you really want it to be a show stopper right when you or a guest walks into the space. Put it up against a wall that can be seen right when you walk in, it will probably be one of your larger splurges so I know you are going to want to show it off!
Plumbing Fixtures: When it comes to the faucet you decide to go with for your vanity I highly recommend a square lined faucet. Something with straight, clean edges that really help with that modern feel. And when it comes to geometric shapes I think a pedestal sink is a way to go as well. Many places offer square vanities that would look perfect with this style. One last fixture that you can easily incorporate into the geometric trend is in the sink you chose. I am a huge fan of overmount sinks and it would look fantastic in a modern style bathroom such as the one you may be going for.
Bathrooms come in many shapes and styles and it is important to pick the style that suits you best. You want to walk into your bathroom and absolutely love it from head to toe. If you think geometric shapes and the modern trend are your things then you should check out Ferguson's website because they offer a wide variety of the trendy products for your bathroom. I hope I was able to inspire you to take a little risk when it comes to the design of your bathroom, after all it is your space and it should be magical.