As character names:

U+2B17 DIAMOND WITH RIGHT HALF BLACK character (⬗)

As raw characters:

⬗

As a string of HTML entities:

⬗

Decoder output:

Byte number 1 is decimal 226, hex 0xE2, octal \342, binary 11100010
This is the first byte of a 3 byte sequence.

Byte number 2 is decimal 172, hex 0xAC, octal \254, binary 10101100
This is continuation byte 1, expecting 1 more.

Byte number 3 is decimal 151, hex 0x97, octal \227, binary 10010111
This is continuation byte 2, expecting 0 more.

U+2B17	DIAMOND WITH RIGHT HALF BLACK