http://book.klll.cc/ebooks/subject/21519.opds?sort_order=title 2025-08-22T03:39:50Z Books about Optical illusions (sorted alphabetically) Free eBooks since 1971. Project Gutenberg https://book.klll.cc webmaster@gutenberg.org https://book.klll.cc/gutenberg/favicon.ico 25 1 2025-08-22T03:39:50Z https://book.klll.cc/ebooks/subject/21519.opds?sort_order=release_date Sort by Release Date 2025-08-22T03:39:50Z https://book.klll.cc/ebooks/subject/21519.opds?sort_order=downloads Sort by Popularity 2025-08-22T03:39:50Z https://book.klll.cc/ebooks/63842.opds Spectropia; or, Surprising Spectral Illusions J. H. Brown 2025-08-22T03:39:50Z https://book.klll.cc/ebooks/36297.opds Visual Illusions: Their Causes, Characteristics and Applications Matthew Luckiesh