RGB LED MATRIX
This circuit is equivalent to a 4x4 RGB LED MATRIX element.
See https://github.com/CircuitVerse/CircuitVerse/pull/343
Pixels can be set in three different ways:

• Method 1: Use inputs R0-R3 and CLR0-CLR3. Others should be disconnected.
  In this mode, pixel at (x,y) takes the color specified by CLRx if CLRx is connected and Ry is 1. This mode provides bulk editing with multiple colors inputs.
  
  
• Method 2: Use inputs R0-R3, C0-C3 and COLOR. Others should be disconnected.
  In this mode, pixel at (x,y) takes the color specified by COLOR if COLOR is connected, Ry is 1 and Cx is 1. This mode provides bulk editing with a single color input.
  
  
• Method 3: Use single pixel ROW, COLUMN and COLOR inputs. Others should be disconnected.
  In this mode, pixel at (COLUMN,ROW) takes the color specified by COLOR if ROW, COLUMN and COLOR are connected. This mode provides single pixel editing.
  
  

If a pixel is affected by multiple methods then method 1 has lowest priority and method 3 has highest priority. In other words, COLOR has precedence over CLRx.
The vertical lines feeding each pixel contain the following signals:

• CLRx
• CLRx is connected
• COLOR
• COLOR is connected
• COLUMN==x
• ROW==y
• Cx
• Ry

The Ry & CLRx' AND gates detect method 1 for a particular pixel.
The Ry & Cx AND gates detect method 2 for a particular pixel.The SINGLE PIXEL AND gates detect method 3 for a particular pixel.The CLR.SEL gate chooses COLOR when method 2 or 3 are selected for a pixel, otherwise it chooses CLRx.The SET PIXEL gate enables the latch to store the new color when an editing method is selected for the corresponding pixel.
Note that in this example each input is hooked to a tri-state and an extra flag, in order to simulate an input being disconnected. The actual RGB LED Matrix does not need these extra flags and simply relies on the inputs being actually connected or not. A circuit controlling an actual RGB LED Matrix can use tri-states to connect and disconnect inputs at runtime, effectively producing the same results as in this sample.