Hi Gungorhilal,
The Delay statement is used to extend the duration of the true value of a result that comes just before. So, you need another statement before the Delay statement.
The Interval instrution is cyclic (True, False, True, False …), no need for instruction before. However, it is possible to stop the instruction by setting an instruction to false just in front.
Conclusion: Everything is normal. I would use the Sequence instruction. The instruction works very well with the Panel LED. Otherwise, you can do an animation directly with the image instruction that comes from the Led Panel block.