A Windmill made from 5 clovers (Asterisk + Windoku), with no givens in the middle grid.
It is an EASY one, because you don't need special methods, except naked/hidden singles, BUT...
Did you know that the 4 constraints of a Windoku is not limited to the 4 boxes. You get 5 extra constraints for free.
See http://www.sudokuwiki.org/Windoku_Strategy
Without use of those extra 5, solving is probably more difficult.
The image :
In text:
#5//E7,aw/N13,aw/H19,aw/B25,aw/K31,aw
300000007000007000800090400700030020000004900908000000000000000670000000280000000
300000005000500000007040002000070008000800000000000706000005000000000029000704061
000000000000000000000000000000000000000000000000000000000000000000000000000000000
910706000670000000000100000106000000000009000200010000800050100000004000700000003
000000028000000057000000000000000601001400000070050002005030009000900000100000003
Import the puzzle into the Solver as follows:
Select the code above and copy (cntl-C) it in the copy/past buffer
Start Notepad
Paste (cntl-V) the copy/paste buffer into the Notepad editor
Save it to "somefile.txt" (with .txt extention)
Start the Solver
In the Solver press the button "FileIn" and select the saved "somefile.txt"
The puzzle will be loaded into sheet SudokuSolver
Press the "Paint"button. Colors may vary, but can be adjusted in the sheet "Colors"