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README.md

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+# Project 1: Maths Puzzles
+
+## Math Puzzle
+- each digit must be 1-9
+- each row contains no repeated digit
+- each column contains no repeated digit
+- all squares on the diagonal line from top left corner to bottom right corner must contain the same value
+- the heading of each row holds either:
+    - the sum of all the digits in that row
+    - the product of all the digits in that row
+- the heading of each column holds either:
+    - the sum of all the digits in that column
+    - the product of all the digits in that column
+
+## Input
+A math puzzle with most/all squares empty **except** for the headings
+
+## Solution
+
+### Structure
+A predicate `puzzle_solution/1` which holds when the argument is a solved math puzzle
+
+### Approach
+Utilise constraint logic programming
+1. unify all squares on the diagonal
+2. check rows are valid
+    1. all distinct
+    2. sum to heading
+    3. product to head
+3. check columns are valid via `transpose/2`