http://book.klll.cc/ebooks/subject/21519.opds?sort_order=downloads 2025-08-24T04:29:52Z Books about Optical illusions (sorted by popularity) Free eBooks since 1971. Project Gutenberg https://book.klll.cc webmaster@gutenberg.org https://book.klll.cc/gutenberg/favicon.ico 25 1 2025-08-24T04:29:52Z https://book.klll.cc/ebooks/subject/21519.opds?sort_order=title Sort Alphabetically by Title 2025-08-24T04:29:52Z https://book.klll.cc/ebooks/subject/21519.opds?sort_order=release_date Sort by Release Date 2025-08-24T04:29:52Z https://book.klll.cc/ebooks/36297.opds Visual Illusions: Their Causes, Characteristics and Applications Matthew Luckiesh 2025-08-24T04:29:52Z https://book.klll.cc/ebooks/63842.opds Spectropia; or, Surprising Spectral Illusions J. H. Brown