Sent in my Resume, 2 months later got an email asking for a phone screen. Phone screen went well, and then received an email asking me to spend a day on a coding challenge. I agreed to the coding challenge, which was to be done over email. They sent me instructions, and I was to reply with a ZIP file of my work based on those instructions in 24 hours. I'm not going to describe the challenge in detail, except that it was one of the most difficult programs I've ever developed, and I've been coding for 10+ years. It was something of a "mini-CAD" program for solar cell layout, that had to also allow the user to rotate the layout by an arbitrary number of degrees. I set down, and gave it all the time I had, which was 24 hours, minus ~6 hours sleep. Got it to a point that it was working roughly as requested, and sent it in before the deadline, but did not even get a reply acknowledgement that they received it. 2+ months later got another email, saying "thank you" and "good luck". Wrote back politely asking if they had any feedback on how I implemented their coding challenge, but there was no response. They did not have to hire me, but their refusal to at least give me some feedback after I spent a day of my life on their task was rude and low class. They did me a favor by rejecting me as the culture there is got to be pretty rough.