Pinhole photography workshop

This is my pinhole camera on a 15 minute exposure...I see this house
every morning when I walk ....it belongs to Chinati foundation .... We
each made the cameras by blacking out reused boxes with lots of duct
tape and black paper, making a pinhole and then inserting a sheet of
photo paper....exposure time is an educated guess based on available
light today, size of pinhole and size of box.... Car just drove by and
I was afraid it would blow over the box, maybe I'll weight it next
time.....