1-8 must be placed in each row, column, and 4x2 box. Every digit is "married" to exactly one other, and married couples share their values, eg. if 3 and 7 are married, then every instance of the digits 3 and 7 in the grid has a value of (3+7), which is 10. The VALUES in a cage must sum to either 37, 26 or 9. Digits and/or values may repeat in a cage. DIGITS separated by a heart are consecutive. Cells separated by a knight's move (in chess) may not contain the same DIGIT.