Kind of class hierachy table. If you have better idea for presenting it,
or want to make some graphics, welcome.
Letters inside [] brackets stand for:
S - Streamable
N - Nameable
T - template

VMObject
    Attack
    Affect[S]
    Action[SN]
        Spell_Action
    Exit[SN]
    Repop
    MudObject
        Room[NS]
        Area[NS]
        Thing[N]
            Char[S]
                PC
                NPC
                    Shopkeeper
            Object[S]
                ObjArmor
                ObjContainer
                ObjCorpse
                ObjLiquidContainer
                ObjGold
                ObjFood
                ObjWeapon

Editor
    RoomEditor
    NPCEditor
    ObjEditor
    AreaEditor
    HelpEditor
    TextEditor

Stream
    OStream
        OutFile
    IStream
        InFile

StringRep
String

Modifier
Index
Weather
Environment
ShopTrade
Social[N]
Help[NS]
Guild[S]

Host
Server
Descriptor
Socket
    SocketBuf
Buf

Error
Spell
Random
countedThing
Vector

Array[TS]
HashNode
HashTable[T]
Node
LList[T]

MemoryBlock
    AsmObjFile
    VMachine
AsmParser
AsmLinker
VMarray