Re: [Rails-devel] Can special tile lays ever be an upgrade?

[Erik V. <eri...@xs...>]

I have started to look after my backlog of old "follow-up" emails.

> From: John David Galt [mailto:jd...@di...]
> Stefan Frey wrote:
> > Some minor bug fixes:
> >
> > A. Special tile lays
> > Currently special tile lays had hardly any checks for its validity.
> >
> > Examples:
> > a) In 1889 the port tile can be laid on a hex already containing a
> > yellow broad curve town tile.
> > b) In 18AL the lumberjack tile can be laid on a hex already containing
> > a yellow broad curve tile.
> > c) In 1830 the D&H allows upgrading to green tiles if a yellow tile
> > was laid already.
> >
> > The following changes prevent this:
> > - Special tile lays always increase tile colour number.
> 
> I don't understand this, unless it means that the tile colour must follow
the
> same progression (from what's already in the hex) as a regular tile lay.
> This is a good general rule, but we need to be able to declare exceptions
in a
> game definition.
> 
> > - Special tile lays always check the allowed tile colour of the current
phase.
> 
> If this is true, I would think it would solve the Pfalz problem (just
notice that
> the hex is already yellow).

Alternatively, can we assume it to be a hard rule that special tile lays
must always be *initial* lays, no upgrades? 
Because that would be a simple check.

Most rule books state this rule in some way or another, although sometimes I
can assert it only by assuming that all usage of the terms "place"/"lay" (as
opposed to "replace"/"upgrade") is deliberately intended to refer to initial
tile lays only.  

Are any specific exceptions known where a special tile lay can be an upgrade
of a tile laid earlier?

Erik.