GridLayout example with error. Why?

bogong

Hello!
I am trying to reproduce this example https://evileg.com/en/post/187/ but code from this example finished with error

qrc:/main.qml:65:5: QML Rectangle: Layout: column (3) should be less than the number of columns (3)
QGridLayoutEngine::addItem: Cell (2, 2) already taken
QGridLayoutEngine::addItem: Cell (3, 2) already taken

And "green" block isn't drawing correctly.
Why is that? What am I missing?

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GridLayout example with error. Why?