Old Sketches - Old Memories

I was browsing my old photos when I stumbled upon these sketches I made five years ago. I was really fond of space - spacecrafts, deep space objects, etc. I'm not really good at drawing but I read somewhere that using grid lines can be useful to achieve a more appealing result so as you can see, I used some lines as a guide. Perhaps it's useful for images with mostly straight lines.

I forgot the names of these crafts but I think I found them in a book I was reading before. If I have time, I will try my best to draw again!