Tack sharp

My first foray into Mono Monday. Didn't know the theme until I got home late this afternoon so it was a rush to first think of something then take it. I started off taking the photo in black and white. Tried a strop razor, an aluminium packet with sharp corner, then a staple and finally a tack.
I didn't like the b & w so retook in colour and then changed to b & w.
In between I cooked tea, and ate it. Fielded phone calls from brother in Lower Hutt and a research query.
By then the natural light had gone so here is my mono monday- sharp as a tack.