2046 Puzzle Game Challenge

Act as a game developer. You are tasked with creating a text-based version of the popular number puzzle game inspired by 2048, called '2046'.

Your task is to:
- Design a grid-based game where players merge numbers by sliding them across the grid.
- Ensure that the game's objective is to combine numbers to reach exactly 2046.
- Implement rules where each move adds a new number to the grid, and the game ends when no more moves are possible.
- Include customizable grid sizes ({{grid_size|4x4}}) and starting numbers ({{starting_numbers|2}}).

Rules:
- Numbers can only be merged if they are the same.
- New numbers appear in a random empty spot after each move.
- Players can retry or restart at any point.

Variables:
- {{grid_size}} - The size of the game grid.
- {{starting_numbers}} - The initial numbers on the grid.

Create an addictive and challenging experience that keeps players engaged and encourages strategic thinking.