How to get the blue diamond in Luigi’s lobby on the first floor

There are several ways to obtain the blue diamonds in Luigi's lobby on the first floor:

1. The gems in the first washing machine can be obtained after Luigi can use the suction cup. .

2. In the picture frame on the left side of the elevator on the B1 floor, the third room where you get the vacuum cleaner after rescuing the doctor is in a car wrapped in a dust jacket.

3. The last one is on the stair mezzanine between the first floor and the first floor. You need to learn how to clone and let the clone get it.

The above is how to obtain the blue diamond in Luigi's lobby on the first floor. I wish you success in getting the gem.