visualize block gas spectrum

[SCBuergel]

• obtain tx receipt per tx and gasUsed from receipt
• store gasUsed per tx in txs object
• visualize next two block output on scale from global minGas to maxGas, display on this 1-dimensional axis that is split into 20 buckets of gray bars in 5 scales:

1. ( )
2. ░ (░)
3. ▒ (▒)
4. ▓ (▓)
5. █ (&block)

• each bucket has a value of gas in this block used within bucket limits of gas prices / total gas used in block which in turn is split to 5 domains which are linearly distributed over the gas usage amount.