Wire an NMOS transistor so that when In is 1, the output is pulled to ground (0). When In is 0, the output should be unconnected (Z).
The way it's worded it sounds like you need 'an NMOS' ie a single one? So I messed around but then I remembered seeing gates made from two transistors in my dusty memory.
(edit) I see there _is_ a one transistor solution... I'm pretty sure I tried that though. :/
If I could make a recommendation, get rid of the grid lines entirely and only have 'dots' at regular spacing. Here's what Cadence Virtuoso looks like (the most popular circuit schematic tool for integrated circuit design):
https://www.eecs.umich.edu/courses/eecs311/f09/tutorials/cad...