Adjacent pentagons

However, the american mathematician george birkhoff showed in 1913 that a particular arrangement of four adjacent pentagons is reducible. scenting scentless sceptical sceptically scepticism sceptics sceptre sceptred sceptres schedule scheduled scheduler schedulers schedules scheduling schematic schematics schismatics schisms schist schistosomiasis schists schizoid schizophrenia schizophrenic schizophrenics schmalz schnapps scholar scholarly scholars scholarship scholarships scholastic scholasticism school schoolboy schoolboys schoolchild schoolchildren schooldays schooled schoolgirl schoolgirls schoolhouse schooling schoolmaster schoolmasters schoolmates schoolmistress schoolroom schools schoolteacher schoolteachers schooner schooners schwa schwas sciatica science sciences scientific scientifically scientist scientists scifi scimitar scimitars scintigraphy scintillate scintillated scintillating scintillation scintillations scintillator scintillators scissor scissored sclerosis scoff scoffed scoffing scolder scones scoop scooped scooper scoopful scooping scoops scoot scooter scooters scooting scoots scope scopes scorch scorched scorcher scorches scorching score scoreboard scoreboards scorecard scorecards scored scoreless scoreline scorer scorers scores scoring scorn scorned scornful scornfully scorning scorns scorpion scorpions scot scotch scotched scotches scotfree scotsman scoundrel scoundrels scour scoured scourge scourged scourges scourging scouring scours scout scouted scouting scoutmaster scoutmasters scouts scowl scowled scowling scowls scrabble scrabbled scrabbling scram scramble scrambled scrambler scramblers scrambles scrambling scrams scrap scrapbook scrapbooks scrape scraped scraper scrapers scrapes scrapie scraping scrapings scrapped scrappier scrappiest scrapping scrappy scraps scrapyard scrapyards scratch scratched scratches scratchier scratchiest scratchiness scratching scratchings scratchy scrawl scrawled scrawling scrawls scrawnier scrawniest scrawny scream screamed screamer screamers screaming screamingly screams scree screeches screechiest screeching screechy screed screeds screen screened screening screenings screenplay screenplays screens screenwriter screw screwdriver screwdrivers screwed screwing screws screwy scribal scribble scribbled scribbler scribblers scribbles scribbling scribblings scribe scribed scribes scribing scrimped