Fill in the grid so that every with an arrow marked line and every bold marked region contains the digits 1 through 8.
The coloured lines in this grid should help to understand the rules:
Put the numbers 1 through 6 into the triangular cells so that every line (in three directions) contains every digit not more than once.
Put the numbers 1 through 6 into the triangular cells so that every line (in three directions) contains every digit not more than once.
Put the numbers 1 through 6 into the triangular cells so that every line (in three directions) contains every digit not more than once.
Put the numbers 1 through 8 into the triangular cells so that every line (of any length, in three directions) and every of the four marked smaller diamonds contains every digit not more than once.
Put the numbers 1 through 8 into the triangular cells so that every line (of any length, in three directions) and every of the four marked smaller diamonds contains every digit not more than once.
Put the numbers 1 through 9 into the triangular cells so that each of 6 large triangles and every line (of any length, even uncontinous) contains every digit not more than once. (Remark: Some lines consist of 8 cells).
Fill the grid with the digits 1 to 8. Lines in each marked line and in the marked 4x2 regions have exactly one of each digit.
Fill in the grid so that every line and the six 3x3 boxes contain two 2's, three 3's and four 4's.
Fill in the grid so that every radial line and every spiral line contains the digits 1 through 5.