Command Block Showcase: Timers Map
If you are designing maps for Minecraft and wish to implement time-limited level completions, check out the map titled «Command Block Showcase: Timers (Showcase of Command Blocks: Timers)».
The image below showcases six different types of timers created using command blocks. Some feature a greater number of command blocks, while others have fewer. Regardless, all are designed for easy copying to your map in Minecraft.
All timers operate on a fixed duration of 10 seconds. Additionally, there are signs explaining how the block setups function.