Hi @gansiiiiiiiii ,
welcome to the arduino-forum.
Well done posting code as a code-section in your very first posting.
The function delay() should have the name
freeze_microcontroller_COMPLETELY_stop_ALL_code_execution_until_freezing_time_is_over()
You have two for-loops() that repeat 180 times and wait 15 milliseconds in each iteration.
This means executing the two for-loops needs
2 * 180 * 0.015 Seconds = 5.4 seconds.
So only once and for a very hsort moment your code
gets executed and then your code is "pausing" again for 5.4 seconds.
This is called blocking code
Here is a link that visualises how your code works and how the cod emust be modified to make the loop non-blocking.
And you have to combine this with non-blocking timing