The answer is SIXTEEN HUNDRED The corresponding square is PENNSYLVANIA AVENUE by Dave Tuller and Michael Rios Each of the three grids can be filled with the letters DEFGHIJNQRSTUWXZ so that each row, column and 4x4 subgrid contains each letter exactly once (and there is only one way to do this). When this is done, a few letters appear in the same place in all three grids, one per column except for two columns that have no such letter. Read left to right, these spell SIXTEEN HUNDRED. For reference, here are the completed grids: UFZQTXRDGISJHEWN GTWNUSEJRHDXIZQF EDXIGNHWFTZQSRUJ RJHSIQFZEUWNGTDX SUQJDRXGWFETNIZH TIGEWZUQNRJHXFSD XRNWFHSIDZQGTUJE ZHFDJETNSXUIQGRW JSEZHGNRQDXUFWIT WNUFSIZTHGREJDXQ DQTHXFJUZNIWESGR IGRXQWDETJFSZHNU FZSGNTQXUWHRDJEI QWDREJIFXSTZUNHG HEITRUGSJQNDWXFZ NXJUZDWHIEGFRQTS IRSHTWFZQJXNUDGE UDNJRIEHGFZWQSTX FGXWQDUSTEHIZRJN ZEQTJNXGRUDSWIHF SZEDUGIXFWJTHNQR WIGFHRJTNZUQEXSD XJRNWFZQDSEHTGIU TUHQDESNIGRXJFWZ ESUGIZHJXDWRFTNQ JNFIESGRHTQUXZDW RHWZXQTDENGFIJUS DQTXNUWFJISZGERH QWJRZTDUSXFGNHEI NXZSGHQEURIJDWFT HTIEFJRWZQNDSUXG GFDUSXNIWHTERQZJ ISDRTUWHQZJXENGF JGWHQNEXRFDIUSTZ ENZUIFJDSWTGQRHX XQFTRGZSNUHEDIWJ SUJEDZHTGIFQWXNR HZXFUWGQTNSRJEID TWNQFXRIZDEJHUSG RIGDJESNUHXWZTFQ FDUWHRIEXJZSTGQN ZTEIXQNWHGUFRJDS QJSGZTDFWRINXHUE NHRXGSUJDEQTFWZI DXHNWJQGFSRUIZET WEQJSDTUIXGZNFRH URISEHFZJTNDGQXW GFTZNIXREQWHSDJU and the overlaps occur as shown below. ****T*********** ******E********* *************R** *********U****** S*************** ***************D **************** *****E*N******** **************** ********H******* **************** ***X************ **************E* **************** **I*******ND**** ****************