Color Sudoku (Solution)
by Byon Garrabrant and Tanya Khovanova
The first eight Sudokus are region Sudokus, where in addition to standard rules you need to satisfy an extra constraint: all letters in one region of color have to be distinct.
Solving Sudokus we get:
Blue Solution
HGD|OTA|WIP WOI|HDP|TGA TAP|GWI|DOH ---+---+--- GDO|PAT|IHW PTW|IHD|OAG IHA|WOG|PTD ---+---+--- DWG|TIH|APO APT|DGO|HWI OIH|APW|GDT
Green Solution
FYH|MSN|ILT MLN|TFI|SHY TSI|YLH|MFN ---+---+--- NHL|FMT|YSI YMT|SIL|FNH SIF|NHY|LTM ---+---+--- HTM|LYS|NIF IFS|HNM|TYL LNY|ITF|HMS
Light Blue Solution
UCW|NFT|ILE ENL|UIC|FTW FTI|EWL|CUN ---+---+--- LIC|TNW|EFU WET|FCU|LNI NFU|ILE|TWC ---+---+--- TUN|CEF|WIL CLF|WUI|NET IWE|LTN|UCF
Orange Solution
HLU|EFP|NSO SPE|NHO|FUL FON|SUL|HPE ---+---+--- PEH|LSN|OFU UNL|FOH|PES OSF|PEU|LNH ---+---+--- LUS|ONF|EHP NHO|UPE|SLF EFP|HLS|UON
Pink Solution
TCM|DNR|YFA ARN|FYM|DTC DFY|ATC|NMR ---+---+--- NAR|TDF|CYM YTC|MAN|RDF FMD|RCY|ANT ---+---+--- MYF|CRD|TAN CDT|NFA|MRY RNA|YMT|FCD
Purple Solution
OCG|API|MUS APS|MCU|OGI UIM|GOS|PCA ---+---+--- MOU|IGA|CSP IGP|CSM|UAO CSA|OUP|GIM ---+---+--- GAC|SMO|IPU SUO|PIC|AMG PMI|UAG|SOC
Red Solution
OEL|CYW|DMA DAC|ELM|YWO MWY|DAO|LEC ---+---+--- EOM|LDC|WAY LYW|OMA|ECD CDA|YWE|MOL ---+---+--- YCE|WOD|ALM ALO|MEY|CDW WMD|ACL|OYE
Yellow Solution
YDR|SPU|WEH PSE|HWD|URY HWU|ERY|DPS ---+---+--- SPD|RYE|HWU EYW|UHP|SDR URH|DSW|PYE ---+---+--- WHY|PUR|ESD DUP|YES|RHW RES|WDH|YUP
After that we notice that the jigsaw sudoku has the same colors, and the overlap of a particular color is always by three cells. This gives us an idea to use the overlap letters as clues for digits.
We get the following clues for the jigsaw Sudoku.
G| NR|I S| |D I | | N ---+---+--- GD | |ESI | | IS | E|L ---+---+--- L | D|A N | ES|R | |
Solving the Jigsaw Sudoku we get
ELG|SNR|IAD ANS|EIG|DLR RIE|LDA|SGN ---+---+--- GDN|RAL|ESI SAL|IRN|GDE ISR|DGE|LNA ---+---+--- LEI|NSD|ARG NGD|AES|RIL DRA|GLI|NES
The colorless white region is the last row and it spells DRAGLINES, which is the answer.