Raspberry pi and Arduino serial communication

Hi, I have a problem with serial communication between Rasp and Arduino. I have written code for both. When I try serial communication on Rasp in Arduino IDE it is working. But when I try serial communication by code on Rasp, it is printing rectangles (in arduino serial monitor) and no what I send from rasp to arduino. So can anyone help me? :)

here is link to photo of arduino serial output https://www.dropbox.com/s/vjvd4p76mmu4ciq/rectangles.png?dl=0

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