Spawn sky symbols
The Spawn sky symbols are a form of art or advertising common at 2b2t's Spawn. They are made facing upwards at the height limit (Y:256) in order to be viewed by Spawn renders, in which they appear prominently. Conveniently, as blocks cannot be placed above Y:256 to cover the art or spawn Withers, these builds are very resistant to griefers. The only way they can be griefed is by manually breaking the obsidian blocks or adding more blocks to the logo to alter the drawing.
The concept was invented in 2018 by Armorsmith shortly after the end of the 6th Incursion, in order to advertise his group in spawn renders made by the community. Further symbols have been constructed by groups such as the SpawnMasons, Emperium, Vortex Coalition, Infinity Incursion, Book Club, and many others. The largest Spawn Sky Symbol in history was constructed by the SpawnMasons in the end of 2019 using Baritone bots, and was named "The Masonic Eclipse". After the construction of the Masonic Eclipse, most of the other symbols were griefed.
A similar type of structure was built by the Highway Workers Union in the nether which depicts the logo of the HWU.
Current Spawn Sky Symbols
The Masonic Eclipse
The Masonic Eclipse is the largest Spawn Sky Symbol on 2b2t and the largest non infrastructural structure on the server. It cuts through many existing Spawn Sky Logos. Over 23 people helped to construct the logo. Automated Bots were programmed to create the logo.
Fun facts by the builder leijurv:
- From the first block of obsidian placed to the last, this project took exactly 8 days, 2 hours, 46 minutes, and 33 seconds
- Finished Christmas eve (Christmas day for European time zones)
- 28,154,762 obsidian
- Averaged 40.15 obsidian placed per second, continuously, for the entire duration
- Averaged 14.83 accounts placing at any given time
- 61 unique Minecraft accounts placed at least 1 section
- 1 section = 144 by 144 blocks (slightly larger than a map art) = 20736 blocks
- There were 1,901 sections (not all were full)
- Highest observed peak was 32 accounts placing simultaneously (real max could be higher though)
- 160x more obsidian than the original SpawnMason logo
- Mined over 3.5 million echests, which is more than 46% of the netherrack mined for a 1x2 tunnel to the world border
- In the peak single hour, which was very close to the end, 307,939 blocks of obsidian were placed. That’s over 85 per second.
- To mine all the obsidian in this logo with Efficiency V picks, it would take 17,597 hours
- At 8 hours a day, with perfect TPS, that’s over six years
- Over two thousand empty shulkers (previously full of echests) have been left behind on the underside of the logo
Obsidian roof
From the center of spawn, 0,0, and expanding outwards, an Obsidian roof has been built and expanded upon over the years by many groups. Currently, the Roof consists of a circle around the Linked Horizon Wall, which has a radius of 2048 blocks.
OWO Symbol
A massive "OWO" was built northwest of Spawn by the Watchmen. It was the second largest symbol at the time. It has been partially griefed by oofplux and Sand_Turtle using Withers due to it being built one block below the height limit.
Vortex Coalition Sky Logo
The Vortex Coalition built their original sky logo on the Minecraft server Constantiam. The logo is a flat version of the group's signature vortex scaled with each cube being 100 by 100 blocks. Two were built and both were at least partially covered up by The Masonic Eclipse.
Swastika
A swastika, one of the most recognizable symbols of the server, was also seen being built as a sky logo at Spawn.
The Axis Logo
The Axis made their obsidian logo directly over the southern canal. It took approximately 60,000 obsidian and 72 hours to build.
Partially Filled In Sky Symbols
The Infinity Incursion Symbol
The Infinity Incursion Symbol was created in November of 2019, to the southeast of spawn. It was one of the largest obsidian structures on the server at the time. Half of the logo is currently filled in due to the roof.
Large Hammer And Sickle
The first obsidian sky logo was built by Armorsmith's Followers. Their goal was to further advertise their group by making its hammer and sickle symbol visible to anyone walking down the -Z Highway or any player who world downloaded or viewed renders of Spawn. For the longest time, the hammer and sickle was the only sky logo at Spawn, and is clearly visible in the 2018 100k Spawn Download map by the SpawnMasons. 
The Large Hammer And Sickle
Hammer And Sickle viewed from above.
View from below the Hammer And Sickle.
The Hammer And Sickle in rainy weather.
Completely Filled In Sky Symbols
Insignia Symbol
The group Insignia made the symbol on the first day of the group's creation. c0mmie_ then covered it all by himself.
Book Club Symbol
The Book Club also attempted to create a symbol at the sky but it was griefed fairly quickly.
Emperium Omega Symbols
The Emperium decided to create 4 different Omega symbols at Spawn, rather than creating a large single logo. They built them about 2000 blocks away from 0,0 on each Axis Highway in the overworld. The Omega sections of these symbols were later filled in with obsidian in an operation by the The Followers of the Crafting Table.
SpawnMason Square And Compass
The second obsidian sky logo was constructed by the SpawnMasons. Their Square And Compass was also constructed to the north of Spawn, just to the southeast of the Hammer and Sickle. This logo was completely filled up by the Obsidian Roof.
Render of the Northern sections of Spawn with the Square And Compass.
