Learn the small things nobody else bothered to learn, and actually finish them.

OddSkills is a quiz and field guide built from 84 finite collections.

Eighty-four collections. Morse code, semaphore, maritime signal flags, the NATO alphabet, Braille, ASL fingerspelling. The flags, shapes, capitals and outlines of 195 countries. Greek, Cyrillic, Arabic and Hebrew letters. Roman numerals, ASCII, a thousand digits of pi. The periodic table, 88 constellations, the genetic code, cloud genera, minerals on the Mohs scale. Roman emperors, popes, Ottoman sultans, English monarchs. 500 paintings. 148 bird calls. 250 landmarks. Fifty-two military aircraft.

Every collection is a closed set. Eighty-eight constellations. A hundred and eighteen elements. Twenty-six letters. Fourteen eight-thousanders. It ends — which means it can be finished, and that is the whole promise.

WHAT'S INSIDE

• Flag quiz — all 195 world flags, plus state, province and city flags
• Geography quiz — countries on the map, capitals, country shapes, rivers and mountains
• Learn Morse code — tap it out on an on-screen sending key, then read it back
• Semaphore, maritime signal flags, the NATO phonetic alphabet, Braille and sign language (ASL) fingerspelling
• Periodic table quiz — all 118 elements
• Constellations — all 88, drawn star by star
• Bird calls — name 148 birds by sight and by song
• 250 world landmarks, planets and moons, dinosaurs, aircraft, trains and ships
• Russian (Cyrillic), Greek, Arabic and Hebrew alphabets, Roman numerals and more
• History quiz — US presidents, Roman emperors, kings and queens, popes, both world wars
• Art history — 500 famous paintings and 50 sculptures

THREE WAYS INTO EVERY COLLECTION

Reference — the complete set, searchable, with sources.
Learn — short lessons that build one idea at a time.
Practice — drills that draw without repetition, in the form each subject actually needs. Send Morse by holding a key. Tap the country on a map. Name the bird from eight seconds of its song. Read a note off the staff.

FIELD NOTES

Finish a session and it is written down: what you practised, how much you got on the first try, and when. Pin the collections you keep coming back to. There is no account, no sign-in and no server — your progress stays on your device.

PARTY MODE

Two to six players, one phone, the same questions in turn, an optional timer and a result screen nobody asked for. Thirty-four collections can be played this way. Party Mode comes with OddSkills Complete.

VERIFIED, NOT SCRAPED

Natural Earth coordinates for the rivers and the borders. IUCN assessments for the species. Callaghan et al. (2021) for the bird ranking. Commons authors and licences on every photograph and recording, named in the app. When something turns out to be wrong, it gets corrected for everyone.

WHAT IS FREE, AND WHAT IS NOT

Five collections are free forever and never counted: Morse Code, World Flags, Country Shapes, Roman Emperors and the Greek Alphabet. Practise them as much as you like.

Every other collection can be read and learned for free — Reference and Learn are never limited. Practice on those collections is one session a day; watching a short video adds one more for that day.

OddSkills Complete is a single payment. It opens all eighty-four collections with no daily limit, unlocks Party Mode, allows twenty- and forty-question sessions, and removes the advertising for good. No subscription, no account, nothing to cancel. Collections added later are included.

Little things to know. Just because.