Live Theme Customizer
Using WordPress Customizer with live preview.

Slideshow Sticky Posts And Gallery
Slideshow Gallery And Sticky Posts on Home

Full-screen Header images
Pages and posts use Featured Image to display a full-screen Header image. Front Page with a Background image. Home Tagline with Text on background image/color.

I have used the Rectangulum theme for two of my websites. I find it to be a unique layout and easy to customise. In my opinion it’s one of the best free themes available for WordPress. Keep up the good work.