... Messages . ... The Object Memory . ... For example, the bytecode 0 always instructs the interpreter to push the value of the receiver's first instance variable on to its stack. ... push the value of the receiver's first instance variable ( origin ) onto the stack . ... The variable names in a source method are converted into instructions to push objects on the stack, the selectors are converted into instructions to send messages, and the uparrow is converted into an instruction to return a result. ...