1) For the buttons on my microwave, I believe they are mix of both iconic and symbolic signifiers. The numbers that appear at the top, along with the triangle (the symbol for start), and the X (the symbol to stop) are examples of symbols. These are culturally learned relationships, and do not have any specific physical relationship with what they represent. On the other hand, I believe the buttons for the stove fan and light are examples of icons. They are imitations of their real-life counterparts and emulate the physical appearance of what they represent.
2) I believe the buttons on my car keys are examples of iconic representations. The lock and unlock buttons look like simplified versions of a locked lock and an unlocked lock. The button to open the trunk looks like a little car with its trunk open. They are abstracted depictions but still have a direct visual connection to their physical counterparts.
3) For the no parking sign, I believe it is a mix of iconic and symbolic signifiers. Near the bottom there is an image of a tow truck pulling a car, this is iconic. It is a direct, yet abstracted version of what an image of a car being towed would look like. The P with a red circle and line through it, along with the red arrow, are examples of symbols. Their relationship to their meaning is culturally informed and arbitrary from what they represent. We know the red circle with a line means "no" because we have learned it even though there is no logical connection with what it is associated with.
