Scratch

here are mesh blocks for rocksandfire:

hostMesh
    | t1 t2 |
    (t1 _ self ownerThatIsA: ScratchFrameMorph) ifNil: [t1 _ (self ownerThatIsA: OffscreenWorldMorph) frame].
    t1 workPane scratchServer
        ifNil:
            [t2 _ ScratchServer new.
            t2 stage: t1 workPane.
            t1 workPane scratchServer: t2].
    t1 workPane scratchServer startHosting

getMeshIPAddress
    | t1 |
    Socket initializeNetwork.
    t1 _ NetNameResolver localHostAddress.
    ^ NetNameResolver stringFromAddress: t1

getMeshIPAddress
    | t1 |
    Socket initializeNetwork.
    t1 _ NetNameResolver localHostAddress.
    ^ NetNameResolver stringFromAddress: t1

isHostingMesh
    | t1 t2 |
    (t1 _ self ownerThatIsA: ScratchFrameMorph) ifNil: [t1 _ (self ownerThatIsA: OffscreenWorldMorph) frame].
    (t2 _ t1 workPane scratchServer) ifNil: [^ false].
    ^ t2 isHosting

joinMesh: t1
    | t2 t3 |
    (t3 _ self ownerThatIsA: ScratchFrameMorph) ifNil: [t3 _ (self ownerThatIsA: OffscreenWorldMorph) frame].
    t2 _ ScratchServer new.
    t2 stage: t3 workPane.
    t3 workPane scratchServer: t2.
    t1 size = 0 ifTrue: [^ ''].
    t3 workPane scratchServer joinSessionAt: t1

and you should be able to figure out the rest from other tuts