Step 4: Form A Yellow Cross On The Top Of The Rubik's Cube
So far we have solved two bottom layers and only the yellow face is left. In this fourth stage of our Rubik's tutorial we want to form a yellow cross on the top of the cube. At this point it doesn't matter if the edge pieces don't match the color of the side center pieces. We will switch them in the fifth step.
There's a short algorithm we have to use: F R U R' U' F'.
Besides the solved position there are three other possible patterns: a dot, an "L" shape or a line as illustrated below. In case of the dot you'll have to do the algorithm three times. When there's an "L" shape then twice. See the picture below to understand how this algorithm changes the top layer of the Rubik's Cube. The orientation of the cube is important, so the "L" shape is twisted as illustrated and the line must be horizontal.

F R U R' U' F'
See the animation below to understand how to hold the puzzle in your hands when you execute the algorithm. Press the play button!
There's another algorighm, very similar to the one presented above which is a shortcut and takes you from the "L" shape directly to the finished yellow cross:
F U R U' R' F'
This is the inverse of the first permutation. Play the animation to see how this is working.
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This is the best W I can imagine on a 3x3 grid. This is a line if you ignore the corners. Use TextPaint.com to draw what you mean by W.
With other kubik, I solved it completely - all codes works corectly.
And I can't find method, how to swap only one center edge without affecting whole kubik. Maybe anyone knows how to?
It helped me a lot! Your efforts are highly appreciated 👍
OOO
XOX
This is what I get, a T-shape. I marked the yellow edges with "O".