First off all, I am very sorry for giving you a bag with freely flying resistors in it and that you have to read the value in the darkness of Congress! In parts this is @Alex 's fault, he once gave me bags of 0805 resistors and I recycled them in this projects, as I only want to use 0603 parts most of the time.

Anywho, there might be a 330k resistor in there instead of a 390k resistor, so according to this fine website, it should blink 3 times per second, instead of 2 times.

https://www.digikey.de/en/resources/conversion-calculators/conversion-calculator-555-timer

Here's the parts list:

• R1, R4 100 Ohm
• R3 150 Ohm
• R2 390k Ohm
• C1 1uF
• D1, D2 RED LED (solder upside down)
• U1 LMC555 timer 3V [Datasheet]

The 555 timer has a chamfer to indicate the side of the first pin.

Btw checkout Berlin's very fine sewage report:

https://data.lageso.de/lageso/corona/corona.html#abwasser