Teach me blocks and other components that make up lossy master/lossy-to-lossless (bad transcode) audios.

According to the definition...
>Blocks are the most telltale sign of a lossy master or transcode. They are small rectangular "blobs" present in the spectral, typically around the cusp of the cutoff or other areas at the fringe of audio data, and sometimes clustered with other blocks. They are very small, but the rectangular shape or clustering should be clearly visible. They will sometimes be obscured by other audio data nearby, but can still poke out. They can be present at many different volumes--sometimes they are very loud (red/orange/pink in SoX), other times they can be quiet (purple/blue in SoX). Regardless of volume, blocks are blocks. Lossy encoders create blocks in the process of saving bits. It is purely a lossy compression technique, meaning their presence indicates that a lossy process was run on a sample or the file. However, not all lossy encoders create blocks at every bitrate, so a track can be transcoded without a single block.

>...They are small rectangular "blobs" present in the spectral, typically around the cusp of the cutoff or other areas at the fringe of audio data, and sometimes clustered with other blocks.

Point me out that rectangular area (use neon green box/circle).

Spectral images are about to follow. TIA