Logic Masters Deutschland e.V.

Normal Sudoku rules apply.
Place the digits 1-9 so that they do not repeat in any row, column, or 3x3 box.

Quadruples
Digits in a circle must appear in the four surrounding cells.

Ten Lines
Each line consists of one or more contiguous groups of cells, each of which sums to 10. These groups of cells cannot overlap. Digits may repeat on lines and even within sums.

The Clouds and Daffodils* are the Ten Lines.
(*creative license - haha)

Special Thanks
To Scojo, as this puzzle was constructed for their weekly prompt, with Quads and Ten Lines chosen at random from a wheel.

The puzzle title comes from the William Wordsworth poem:
"I Wandered Lonely as a Cloud".

To play this puzzle please click here: Play CTC

Ten Lines
Please see below for examples of a valid Ten Line fill:

• 4+6, 5+5, 3+2+5 all sum to 10.
• 7+3, 9+1, 2+8 all sum to 10.

Hint - Where to start

The 1789 Quad / Ten Lines combination is very forcing, and does a lot of damage in the top 3 Rows.

Hint - Where to look next

You can make some maths deductions in Row 4, and limit the options, but don't stick around on Row 4 for too long as it disambiguates later.

Hint - Mid to late solve, once you have over half the digits placed

Consider where placing 9 in Column 3 will cause issues.