Tutorial 1

Tutorial 8 - Finding Loops in "Fata Morgana" (Advanced)

This tutorial shows how to place layers and search for rank 0 loops in monsters like Fata Morgana.

On startup Xsudo will open the default puzzle file xsudon.sud. This file contains the tutorials and other interesting examples. The default file cannot be erased.

Open the Tutorial 8 Puzzle

· Open the dropdown puzzle list in the toolbar by clicking on the tab located on the right.

· Scroll to find and select the puzzle Tutorial 8, Fata Morgana, Layers.

· Click on the load puzzle icon to the right.

You will now see the Fata Morgana puzzle with no logic.

Setup

Initial Setup

· Click the [A] in the word in the top toolbar to set auto fill links on.

Enter row-column (RC) layers

Enter RC layers for digits 1, 3, and 6

· Rightclick any digit 1 and select [Add/Sub Plane of Truths] / [RC Plane].

· Repeat the same for digits 3 and 6.

You should see all row/column truths (red/green) in layers 1,3, and 6 plus links between them.

Complete the Layers with 2 cell truths

Place cell truths in r54 and c5c6 to complete logic

· Rightclick digit 1 in r5c4, then select [Add Sub Truth] / [Cell] .

· Repeat for any digit in r5c6.

Eliminations appear for these layers. (Note, there may be other eliminations for these layers)

Cleanup the logic

Switch to the manual logic entry mode.

· Click the [T] in the word in the top toolbar to select manual edit.

Remove unused truths and unused links.

· Select [LogicTools] / [Convert Truths to Links] to remove extra truths.

· Select [LogicTools] / [Remove Unused Links] to remove unused links.

The logic now has 23 truths and many cannibal eliminations. This usually means there are smaller loops.

85 Candidates

23 Sets {1C1245689 3C1245678 6C2345689 5N46}

35 Links {1r134569 3r234569 6r134568 4n2 37n4 19n5 37n6 6n8 1b578 3b589 6b589}

Finding a minimum loop

Fata Morgana has a number of possible loops. To find a minimum loop we will try to remove a few sets that are causing the cannibal eliminations.

Remove digit 1 columns 1c4 and 1c6.

· Rightclick any digit 1 in column 4 and select [Add/Sub Truth] / [Column].

· Repeat the same for digit 1 in column 6.

Again, remove unused truths and unused links.

· Select [LogicTools] / [Convert Truths to Links] to remove extra truths.

· Select [LogicTools] / [Remove Unused Links] to remove unused links.

This is the original Fata Morgana first loop.

Note, there are no bi-value sets, one reason that FM is difficult for some solvers.

Look for Rank 0 links in 3D

Viewing logic in 3D can sometimes help show details. Note, a small crosshair marks the position where a view is frozen.

Switch to 3D

· Place the cursor near 5r5c5 (spatial center) and double right click the mouse.

· Move the mouse up/down and left/right to rotate the view.

· Freeze the view at a desired position with a single rightclick.

Highlight rank 0 links

· Select [LogicView] / [Black Rank 0 links] to highlight rank 0 links.

Switch back to 2D

· (optional) Single rightclick again on the small crosshairs to continue rotation.

· Return to 2D by double rightclicking anywhere in the grid.